WorldWideScience

Sample records for plasticity human behavior

  1. Modeling activity-dependent plasticity in BCM spiking neural networks with application to human behavior recognition.

    Science.gov (United States)

    Meng, Yan; Jin, Yaochu; Yin, Jun

    2011-12-01

    Spiking neural networks (SNNs) are considered to be computationally more powerful than conventional NNs. However, the capability of SNNs in solving complex real-world problems remains to be demonstrated. In this paper, we propose a substantial extension of the Bienenstock, Cooper, and Munro (BCM) SNN model, in which the plasticity parameters are regulated by a gene regulatory network (GRN). Meanwhile, the dynamics of the GRN is dependent on the activation levels of the BCM neurons. We term the whole model "GRN-BCM." To demonstrate its computational power, we first compare the GRN-BCM with a standard BCM, a hidden Markov model, and a reservoir computing model on a complex time series classification problem. Simulation results indicate that the GRN-BCM significantly outperforms the compared models. The GRN-BCM is then applied to two widely used datasets for human behavior recognition. Comparative results on the two datasets suggest that the GRN-BCM is very promising for human behavior recognition, although the current experiments are still limited to the scenarios in which only one object is moving in the considered video sequences.

  2. Two distinct interneuron circuits in human motor cortex are linked to different subsets of physiological and behavioral plasticity.

    Science.gov (United States)

    Hamada, Masashi; Galea, Joseph M; Di Lazzaro, Vincenzo; Mazzone, Paolo; Ziemann, Ulf; Rothwell, John C

    2014-09-17

    How does a single brain region participate in multiple behaviors? Here we argue that two separate interneuron circuits in the primary motor cortex (M1) contribute differently to two varieties of physiological and behavioral plasticity. To test this in human brain noninvasively, we used transcranial magnetic stimulation (TMS) of M1 hand area to activate two independent sets of synaptic inputs to corticospinal neurons by changing the direction of current induced in the brain: posterior-to-anterior current (PA inputs) and anterior-to-posterior current (AP inputs). We demonstrate that excitability changes produced by repetitive activation of AP inputs depend on cerebellar activity and selectively alter model-based motor learning. In contrast, the changes observed with repetitive stimulation of PA inputs are independent of cerebellar activity and specifically modulate model-free motor learning. The findings are highly suggestive that separate circuits in M1 subserve different forms of motor learning.

  3. Mechanoelectrochemical behavior and plasticity of magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Eliezer, A.; Gutman, E.M.; Abramov, E.; Aghion, E. [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Materials Engineering

    1998-12-31

    The mechanical properties and mechanoelectrochemical effect (the effect of mechanical deformation on the surface electrochemical reactions) were investigated for some Mg-based alloys supposing that aluminum alloying influences them. A simple method of testing mechanoelectrochemical behavior of metals was developed. Potentiostatic polarization measurements on stressed electrode were carried out in chloride electrolyte. The correlation between the mechanoelectrochemical behavior and strain hardening stages is observed during plastic deformation. Maximum mechanoelectrochemical effect is achieved under intense strain hardening in the initial portion of this stage. The experimental observations are explained theoretically. (orig.) 9 refs.

  4. Neural plasticity and behavior - sixty years of conceptual advances.

    Science.gov (United States)

    Sweatt, J David

    2016-10-01

    acquisition of behavioral change was an influential discovery in the neurochemistry of behavioral modification. Higher order cognitive functions such as decision making and spatial and language learning were also discovered to hinge on neural plasticity mechanisms. The role of disruption of these processes in intellectual disabilities, memory disorders, and drug addiction has recently been clarified based on modern genetic techniques, including in the human. The area of neural plasticity and behavior has seen tremendous advances over the last six decades, with many of those advances being specifically in the neurochemistry domain. This review provides an overview of the progress in the area of neuroplasticity and behavior over the life-span of the Journal of Neurochemistry. To organize the broad literature base, the review collates progress into fifteen broad categories identified as 'conceptual advances', as viewed by the author. The fifteen areas are delineated in the figure above. This article is part of the 60th Anniversary special issue.

  5. VISCO-ELASTIC (PLASTIC) EFFECTS AND FAILURE BEHAVIOR OF PUR FOAMED PLASTICS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The viscous effects and failure behavior of PUR foamed plastics are investigated by the cycling loading and preloading experiments. On the basis of static and dynamic compressive experiments, the SEM analysis is given for the PUR foamed plastics specimens which have been tested and the deformation as well as failure mechanisms are determined at the same time. In addition, the relaxation characteristics and the failure criterion of foamed plastics are discussed adequately.

  6. On Aerobic Exercise and Behavioral and Neural Plasticity

    Directory of Open Access Journals (Sweden)

    Caitlin Peplinski

    2012-11-01

    Full Text Available Aerobic exercise promotes rapid and profound alterations in the brain. Depending upon the pattern and duration of exercise, these changes in the brain may extend beyond traditional motor areas to regions and structures normally linked to learning, cognition, and emotion. Exercise-induced alterations may include changes in blood flow, hormone and growth factor release, receptor expression, angiogenesis, apoptosis, neurogenesis, and synaptogenesis. Together, we believe that these changes underlie elevations of mood and prompt the heightened behavioral plasticity commonly observed following adoption of a chronic exercise regimen. In the following paper, we will explore both the psychological and psychobiological literatures relating to exercise effects on brain in both human and non-human animals and will attempt to link plastic changes in these neural structures to modifications in learned behavior and emotional expression. In addition, we will explore the therapeutic potential of exercise given recent reports that aerobic exercise may serve as a neuroprotectant and can also slow cognitive decline during normal and pathological aging.

  7. The molecular interfacial structure and plasticizer migration behavior of "green" plasticized poly(vinyl chloride).

    Science.gov (United States)

    Zhang, Xiaoxian; Li, Yaoxin; Hankett, Jeanne M; Chen, Zhan

    2015-02-14

    Tributyl acetyl citrate (TBAC), a widely-used "green" plasticizer, has been extensively applied in products for daily use. In this paper, a variety of analytical tools including sum frequency generation vibrational spectroscopy (SFG), coherent anti-Stokes Raman spectroscopy (CARS), contact angle goniometry (CA), and Fourier transform infrared spectroscopy (FTIR) were applied together to investigate the molecular structures of TBAC plasticized poly(vinyl chloride) (PVC) and the migration behavior of TBAC from PVC-TBAC mixtures into water. We comprehensively examine the effects of oxygen and argon plasma treatments on the surface structures of PVC-TBAC thin films containing various bulk percentages of plasticizers and the leaching behavior of TBAC into water. It was found that TBAC is a relatively stable PVC plasticizer compared to traditional non-covalent plasticizers but is also surface active. Oxygen plasma treatment increased the hydrophilicity of TBAC-PVC surfaces, but did not enhance TBAC leaching. However, argon plasma treatment greatly enhanced the leaching of TBAC molecules from PVC plastics to water. Based on our observations, we believe that oxygen plasma treatment could be applied to TBAC plasticized PVC products to enhance surface hydrophilicity for improving the biocompatibility and antibacterial properties of PVC products. The structural information obtained in this study will ultimately facilitate a molecular level understanding of plasticized polymers, aiding in the design of PVC materials with improved properties.

  8. Stress Dependence of Transformation Plastic Behavior

    Institute of Scientific and Technical Information of China (English)

    Tatsuo Inoue

    2004-01-01

    Transformation plasticity is known to play an important role in the course of heat treatment processes, and so affect the results of heat treatment simulations, which means that the transformation plasticity coefficient is necessary to be identifies. The authors developed a new method by use of four-point bending system of a beam to identify transformation plasticity coefficient taking advantage of its easiness and high accuracy compared with other conventional methods like tension test, etc., and identified the coefficient for four kinds of steels; plane carbon steel, Cr-steel, Cr-Mo steel and bearing steel. In this paper, further experimental data are presented for the steels if the coefficient Kp during pearlite transformation depend on the applied stress. Obtained results reveals that the stress dependence of Kp is rather trivial except for uncertain tendency detected in plane carbon steel. The relation between the Kp and carbon content included is

  9. Human mirror neuron system and its plasticity

    Institute of Scientific and Technical Information of China (English)

    Wei Chen; Tifei Yuan; Yin Wang; Jun Ding

    2008-01-01

    The mirror neuron system (MNS) was first discovered in non-human primates; these neurons fire when a monkey performs an action or observes another monkey (or even some people) performing that same action. Recent findings have suggested that neural rehabilitation might be achieved through the activation of the MNS in patients after stroke. We propose two major mechanisms (one involving adult neurogenesis and another involving brain-derived neurotrophic factor) that may underlie the activation, modulation and expe-rience-dependent plasticity in the MNS, for further study on promoting central nerve functional reconstruc-tion and rehabilitation of patients with central nervous system injury.

  10. Humanism vs. Behaviorism

    Science.gov (United States)

    Hunter, Madeline

    1977-01-01

    Author argues that humanism and behaviorism are not necessarily exclusive of one another, and that principles of behaviorism, when thoughtfully applied, can lead to the achievement of humanistic goals. (RW)

  11. Bridging Humanism and Behaviorism.

    Science.gov (United States)

    Chu, Lily

    1980-01-01

    Humanistic behaviorism may provide the necessary bridge between behaviorism and humanism. Perhaps the most humanistic approach to teaching is to learn how certain changes will help students and how these changes can be accomplished. (Author/MLF)

  12. Bending behavior of lapped plastic ehv cables

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, G H; Muller, A C

    1980-01-01

    One of the factors delaying the development of lapped polymeric cables has been their reputed poor bending characteristics. Complementary programs were begun at BNL several years ago to mathematically model the bending of synthetic tape cables and to develop novel plastic tapes designed to have moduli more favorable to bending. A series of bend tests was recently completed to evaluate the bending performance of several tapes developed for use in experimental superconducting cables. The program is discussed and the results of the bend tests are summarized.

  13. Becoming a mother-circuit plasticity underlying maternal behavior.

    Science.gov (United States)

    Elyada, Yishai M; Mizrahi, Adi

    2015-12-01

    The transition to motherhood is a dramatic event during the lifetime of many animals. In mammals, motherhood is accompanied by hormonal changes in the brain that start during pregnancy, followed by experience dependent plasticity after parturition. Together, these changes prime the nervous system of the mother for efficient nurturing of her offspring. Recent work has described how neural circuits are modified during the transition to motherhood. Here we discuss changes in the auditory cortex during motherhood as a model for maternal plasticity in sensory systems. We compare classical plasticity paradigms with changes that arise naturally in mothers, highlighting current efforts to establish a mechanistic understanding of plasticity and its different components in the context of maternal behavior.

  14. Human-Specific Cortical Synaptic Connections and Their Plasticity: Is That What Makes Us Human?

    Science.gov (United States)

    Lourenço, Joana; Bacci, Alberto

    2017-01-01

    One outstanding difference between Homo sapiens and other mammals is the ability to perform highly complex cognitive tasks and behaviors, such as language, abstract thinking, and cultural diversity. How is this accomplished? According to one prominent theory, cognitive complexity is proportional to the repetition of specific computational modules over a large surface expansion of the cerebral cortex (neocortex). However, the human neocortex was shown to also possess unique features at the cellular and synaptic levels, raising the possibility that expanding the computational module is not the only mechanism underlying complex thinking. In a study published in PLOS Biology, Szegedi and colleagues analyzed a specific cortical circuit from live postoperative human tissue, showing that human-specific, very powerful excitatory connections between principal pyramidal neurons and inhibitory neurons are highly plastic. This suggests that exclusive plasticity of specific microcircuits might be considered among the mechanisms endowing the human neocortex with the ability to perform highly complex cognitive tasks. PMID:28103228

  15. Mechanical behavior of plastic materials for automobile cockpit module

    Science.gov (United States)

    Woo, Changsu.; Park, Hyunsung.; Jo, Jinho.

    2013-12-01

    Engineering plastics are used in instrument panels, interior trims, and other vehicle applications, and the thermo-mechanical behaviors of plastic materials are strongly influenced by many environmental factors such as temperature, sunlight, and rain. As the material properties change, the mechanical parts create unexpected noise. In this study, the dynamic mechanical property changes of plastics used in automobiles are measured to investigate the effect of temperature. Visco-elastic properties such as the glass transition temperature and storage modulus and loss factors under temperature and frequency sweeps were measured. The data results were compared with the original ones before aging to analyze the behavioral changes. It was found that as the temperature increased, the storage modulus decreased and the loss factor increased slightly.

  16. Stress, stress hormones, and the behavioral neurobiology of brain plasticity

    NARCIS (Netherlands)

    Bohus, B; Luiten, PGM; Beldhuis, HJA; vanderZee, EA; Roozendaal, B; Douma, B; Ishikawa, K; McGaugh, JL; Sakata, H

    1996-01-01

    Efforts have long been directed toward studying stress-induced alterations via stress hormones on brain excitability and synaptic plasticity as inferred from combined behavioral, electrophysiological, and immunohistochemical cellular/molecular observations. Kindling of the brain in the rat serves as

  17. The relations between neuroscience and human behavioral science.

    OpenAIRE

    Strumwasser, F.

    1994-01-01

    Neuroscience seeks to understand how the human brain, perhaps the most complex electrochemical machine in the universe, works, in terms of molecules, membranes, cells and cell assemblies, development, plasticity, learning, memory, cognition, and behavior. The human behavioral sciences, in particular psychiatry and clinical psychology, deal with disorders of human behavior and mentation. The gap between neuroscience and the human behavioral sciences is still large. However, some major advances...

  18. The impact of synapsins on synaptic plasticity and cognitive behaviors

    Institute of Scientific and Technical Information of China (English)

    Lin ZHANG; Zhong-Xin ZHAO

    2006-01-01

    Synapsins are a family of phosphoproteins specifically associated with the cytoplasmic surface of the synaptic vesicle membrane, appearing to regulate neurotransmitter release, the formation and maintenance of synaptic contacts.They could induce the change of the synaptic plasticity to regulate various adaptation reactions, and change the cognitive behaviors. So we presume that if some cognitive behavior are damaged, synapsins would be changed as well. This gives us a new recognition of better diagnosis and therapy of cognitive disorder desease.

  19. Chronic alcohol alters rewarded behaviors and striatal plasticity

    OpenAIRE

    DePoy, Lauren; Daut, Rachel; Wright, Tara; Camp, Marguerite; Crowley, Nicole; Noronha, Bianca; Lovinger, David; Holmes, Andrew

    2014-01-01

    Chronic intermittent ethanol (CIE) alters neural functions and behaviors mediated by the dorsolateral striatum (DLS) and prefrontal cortex. Here, we examined the effects of prolonged (16-bout) CIE on DLS plasticity and DLS-mediated behaviors. Ex vivo electrophysiological recordings revealed loss in efficacy of DLS synaptically induced activation and absent long-term depression after CIE. CIE increased two-bottle choice drinking and impaired Pavlovian-to-instrumental transfer but not discrimin...

  20. Use of polycarbonate plastic products and human health

    OpenAIRE

    R. K. Srivastava; Sushila Godara

    2013-01-01

    As plastic and plastic products are being used in day to day at the cost of environment pollution, the human and wild life health and has become a global concern. Researchers found link between abnormal liver enzymes in the people and Bisphenol-A (BPA). Changes in insulin resistance, reproduction system, cardiovascular and brain function are also reported. BPA is used in the production of epoxy resins, polycarbonate resins, and polyester resins. BPA can leach out of certain plastic products i...

  1. Human Computer Confluence in Rehabilitation: Digital Media Plasticity and Human Performance Plasticity

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis

    2013-01-01

    approaches promoting mindsets and activities commonly considered enduring, mundane and boring. The concept focuses on sensor-based interfaces mapped to control tailored-content that acts as direct and immediate feedbacks mirroring input. These flexible, adaptive, and ‘plastic’ options offer facilitators new......Digital media plasticity evocative to embodied interaction is presented as a utilitarian tool when mixed and matched to target human performance potentials specific to nuance of development for those with impairment. A distinct intervention strategy trains via alternative channeling of external...

  2. Training-induced behavioral and brain plasticity in inhibitory control

    OpenAIRE

    Lucas eSpierer; Camille eChavan; Aurelie Lynn Manuel

    2013-01-01

    Deficits in inhibitory control, the ability to suppress ongoing or planned motor or cognitive processes, contribute to many psychiatric and neurological disorders. The rehabilitation of inhibition-related disorders may therefore benefit from neuroplasticity-based training protocols aiming at normalizing inhibitory control proficiency and the underlying brain networks. Current literature on training-induced behavioral and brain plasticity in inhibitory control suggests that improvements may fo...

  3. Musical Training Induces Functional Plasticity in Human Hippocampus

    OpenAIRE

    2010-01-01

    Training can change the functional and structural organization of the brain, and animal models demonstrate that the hippocampus formation is particularly susceptible to training-related neuroplasticity. In humans, however, direct evidence for functional plasticity of the adult hippocampus induced by training is still missing. Here, we used musicians' brains as a model to test for plastic capabilities of the adult human hippocampus. By using functional magnetic resonance imaging optimized for ...

  4. Glutamatergic metabolites are associated with visual plasticity in humans.

    Science.gov (United States)

    Wijtenburg, S Andrea; West, Jeffrey; Korenic, Stephanie A; Kuhney, Franchesca; Gaston, Frank E; Chen, Hongji; Roberts, Meredith; Kochunov, Peter; Hong, L Elliot; Rowland, Laura M

    2017-02-10

    Long-term potentiation (LTP) is a basic cellular mechanism underlying learning and memory. LTP-like plasticity in the visual cortex can be induced by high frequency visual stimulation in rodents and humans. Since glutamate plays a fundamental role in LTP, this study investigated if visual cortical glutamate and glutamine levels, measured by proton magnetic resonance spectroscopy (MRS), relate to visual plasticity in humans. Since plasticity requires a delicate excitation and inhibition balance, GABA was also explored. Eighteen healthy participants completed MRS and a visual fMRI paradigm. Results revealed enhanced fMRI activations after high frequency visual stimulation, suggesting visual plasticity occurred. Higher activations were associated with higher resting glutamine levels after family wise error-correction. Exploratory analyses revealed that higher resting glutamate and GABA levels were associated with visual plasticity, suggesting there may be a critical excitation-inhibition balance necessary for experience dependent plasticity. This is the first empirical evidence that resting glutamine levels and potentially glutamate and GABA levels are associated with visual plasticity in humans.

  5. Plasticity resembling spike-timing dependent synaptic plasticity: the evidence in human cortex

    Directory of Open Access Journals (Sweden)

    Florian Müller-Dahlhaus

    2010-07-01

    Full Text Available Spike-timing dependent plasticity (STDP has been studied extensively in a variety of animal models during the past decade but whether it can be studied at the systems level of the human cortex has been a matter of debate. Only recently newly developed non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS have made it possible to induce and assess timing dependent plasticity in conscious human subjects. This review will present a critical synopsis of these experiments, which suggest that several of the principal characteristics and molecular mechanisms of TMS-induced plasticity correspond to those of STDP as studied at a cellular level. TMS combined with a second phasic stimulation modality can induce bidirectional long-lasting changes in the excitability of the stimulated cortex, whose polarity depends on the order of the associated stimulus-evoked events within a critical time window of tens of milliseconds. Pharmacological evidence suggests an NMDA receptor mediated form of synaptic plasticity. Studies in human motor cortex demonstrated that motor learning significantly modulates TMS-induced timing dependent plasticity, and, conversely, may be modulated bidirectionally by prior TMS-induced plasticity, providing circumstantial evidence that long-term potentiation-like mechanisms may be involved in motor learning. In summary, convergent evidence is being accumulated for the contention that it is now possible to induce STDP-like changes in the intact human central nervous system by means of TMS to study and interfere with synaptic plasticity in neural circuits in the context of behaviour such as learning and memory.

  6. Human Maternal Brain Plasticity: Adaptation to Parenting

    Science.gov (United States)

    Kim, Pilyoung

    2016-01-01

    New mothers undergo dynamic neural changes that support positive adaptation to parenting and the development of mother-infant relationships. In this article, I review important psychological adaptations that mothers experience during pregnancy and the early postpartum period. I then review evidence of structural and functional plasticity in human…

  7. Human Maternal Brain Plasticity: Adaptation to Parenting

    Science.gov (United States)

    Kim, Pilyoung

    2016-01-01

    New mothers undergo dynamic neural changes that support positive adaptation to parenting and the development of mother-infant relationships. In this article, I review important psychological adaptations that mothers experience during pregnancy and the early postpartum period. I then review evidence of structural and functional plasticity in human…

  8. Superstitious behavior in humans.

    Science.gov (United States)

    Ono, K

    1987-05-01

    Twenty undergraduate students were exposed to single response-independent schedules of reinforcer presentation, fixed-time or variable-time, each with values of 30 and 60 s. The reinforcer was a point on a counter accompanied by a red lamp and a brief buzzer. Three color signals were presented, without consistent relation to reinforcer or to the subjects' behavior. Three large levers were available, but the subjects were not asked to perform any particular behavior. Three of the 20 subjects developed persistent superstitious behavior. One engaged in a pattern of lever-pulling responses that consisted of long pulls after a few short pulls; the second touched many things in the experimental booth; the third showed biased responding called sensory superstition. However, most subjects did not show consistent superstitious behavior. Reinforcers can operate effectively on human behavior even in the absence of a response-reinforcer contingency and can, in some cases, shape stable superstitious patterns. However, superstitious behavior is not a consistent outcome of exposure of human subjects to response-independent reinforcer deliveries.

  9. Behaviour and Environment - A Behavioral Study of no Use of Plastic Bags' Intention

    Directory of Open Access Journals (Sweden)

    Eliane Bragança de Matos

    2013-06-01

    Full Text Available The perception of the environmental impact of current consumption patterns and the increasing centrality of this discourse in international environmentalism’s mainstream bring new perspectives and arguments concerning the consumerism of contemporary Western societies. From this perspective, the central question of this project was: “What is the intention of not using plastic bags?” Using as a theoretical reference the Planned Behavior Theory, which seeks to understand and predict human behavior in a general way from a reduced set of antecedent variables, we developed an intersectional survey consisting of 226 interviews. Data were processed by equations modeling and treated in Amos 16.0 software. The measurement model considered the mental constructions forming TCP. It was possible to identify as a major contribution of this study that the perceived behavioral control is the most influential factor on the intended not use of plastic bags, hindering the adoption of the behavior of not using plastic bags. Perhaps the fact that it is a settled habit, which involves several routine actions, such as the habit of going to the grocery store and have to plan in advance to take the alternative shopping bag or cart for packaging purchased products, or to count on ecological alternatives offered by commercial establishments, is a major and determining impediment for behavioral change.

  10. Human pancreatic islet progenitor cells demonstrate phenotypic plasticity in vitro

    Indian Academy of Sciences (India)

    Maithili P Dalvi; Malati R Umrani; Mugdha V Joglekar; Anandwardhan A Hardikar

    2009-10-01

    Phenotypic plasticity is a phenomenon that describes the occurrence of 2 or more distinct phenotypes under diverse conditions. This article discusses the work carried out over the past few years in understanding the potential of human pancreatic islet-derived progenitors for cell replacement therapy in diabetes. The phenotypic plasticity exhibited by pancreatic progenitors during reversible epithelial-to-mesenchymal transition (EMT) and possible role of microRNAs in regulation of this process is also presented herein.

  11. Visual attentional load influences plasticity in the human motor cortex.

    Science.gov (United States)

    Kamke, Marc R; Hall, Michelle G; Lye, Hayley F; Sale, Martin V; Fenlon, Laura R; Carroll, Timothy J; Riek, Stephan; Mattingley, Jason B

    2012-05-16

    Neural plasticity plays a critical role in learning, memory, and recovery from injury to the nervous system. Although much is known about the physical and physiological determinants of plasticity, little is known about the influence of cognitive factors. In this study, we investigated whether selective attention plays a role in modifying changes in neural excitability reflecting long-term potentiation (LTP)-like plasticity. We induced LTP-like effects in the hand area of the human motor cortex using transcranial magnetic stimulation (TMS). During the induction of plasticity, participants engaged in a visual detection task with either low or high attentional demands. Changes in neural excitability were assessed by measuring motor-evoked potentials in a small hand muscle before and after the TMS procedures. In separate experiments plasticity was induced either by paired associative stimulation (PAS) or intermittent theta-burst stimulation (iTBS). Because these procedures induce different forms of LTP-like effects, they allowed us to investigate the generality of any attentional influence on plasticity. In both experiments reliable changes in motor cortex excitability were evident under low-load conditions, but this effect was eliminated under high-attentional load. In a third experiment we investigated whether the attentional task was associated with ongoing changes in the excitability of motor cortex, but found no difference in evoked potentials across the levels of attentional load. Our findings indicate that in addition to their role in modifying sensory processing, mechanisms of attention can also be a potent modulator of cortical plasticity.

  12. Augmenting Plasticity Induction in Human Motor Cortex by Disinhibition Stimulation.

    Science.gov (United States)

    Cash, Robin F H; Murakami, Takenobu; Chen, Robert; Thickbroom, Gary W; Ziemann, Ulf

    2016-01-01

    Cellular studies showed that disinhibition, evoked pharmacologically or by a suitably timed priming stimulus, can augment long-term plasticity (LTP) induction. We demonstrated previously that transcranial magnetic stimulation evokes a period of presumably GABA(B)ergic late cortical disinhibition (LCD) in human primary motor cortex (M1). Here, we hypothesized that, in keeping with cellular studies, LCD can augment LTP-like plasticity in humans. In Experiment 1, patterned repetitive TMS was applied to left M1, consisting of 6 trains (intertrain interval, 8 s) of 4 doublets (interpulse interval equal to individual peak I-wave facilitation, 1.3-1.5 ms) spaced by the individual peak LCD (interdoublet interval (IDI), 200-250 ms). This intervention (total of 48 pulses applied over ∼45 s) increased motor-evoked potential amplitude, a marker of corticospinal excitability, in a right hand muscle by 147% ± 4%. Control experiments showed that IDIs shorter or longer than LCD did not result in LTP-like plasticity. Experiment 2 indicated topographic specificity to the M1 hand region stimulated by TMS and duration of the LTP-like plasticity of 60 min. In conclusion, GABA(B)ergic LCD offers a powerful new approach for augmenting LTP-like plasticity induction in human cortex. We refer to this protocol as disinhibition stimulation (DIS).

  13. Behavioral Response to Plastic Bag Legislation in Botswana

    OpenAIRE

    2010-01-01

    This paper investigates the use of charges and standards in dealing with a common externality, plastic litter from shopping bags in Botswana. The country passed a plastic bag tax (effective 2007) to curb the plastic bag demand. Interestingly, the legislation did not force retailers to charge for plastic bags, which they did voluntarily at different prices. We assessed the environmental effectiveness and efficiency of the plastic bag legislation by analyzing consumers’ sensitivity to the impro...

  14. Structural plasticity in human heterochromatin protein 1β.

    Directory of Open Access Journals (Sweden)

    Francesca Munari

    Full Text Available As essential components of the molecular machine assembling heterochromatin in eukaryotes, HP1 (Heterochromatin Protein 1 proteins are key regulators of genome function. While several high-resolution structures of the two globular regions of HP1, chromo and chromoshadow domains, in their free form or in complex with recognition-motif peptides are available, less is known about the conformational behavior of the full-length protein. Here, we used NMR spectroscopy in combination with small angle X-ray scattering and dynamic light scattering to characterize the dynamic and structural properties of full-length human HP1β (hHP1β in solution. We show that the hinge region is highly flexible and enables a largely unrestricted spatial search by the two globular domains for their binding partners. In addition, the binding pockets within the chromo and chromoshadow domains experience internal dynamics that can be useful for the versatile recognition of different binding partners. In particular, we provide evidence for the presence of a distinct structural propensity in free hHP1β that prepares a binding-competent interface for the formation of the intermolecular β-sheet with methylated histone H3. The structural plasticity of hHP1β supports its ability to bind and connect a wide variety of binding partners in epigenetic processes.

  15. Human Structural Plasticity at Record Speed

    Science.gov (United States)

    Johansen-Berg, Heidi; Baptista, Cassandra Sampaio; Thomas, Adam G.

    2012-01-01

    How rapidly does learning shape our brains? A new study using diffusion magnetic resonance imaging in both humans and rats suggests that just two hours of spatial learning is sufficient to change brain structure. PMID:22445333

  16. Satellite cells in human skeletal muscle plasticity.

    Science.gov (United States)

    Snijders, Tim; Nederveen, Joshua P; McKay, Bryon R; Joanisse, Sophie; Verdijk, Lex B; van Loon, Luc J C; Parise, Gianni

    2015-01-01

    Skeletal muscle satellite cells are considered to play a crucial role in muscle fiber maintenance, repair and remodeling. Our knowledge of the role of satellite cells in muscle fiber adaptation has traditionally relied on in vitro cell and in vivo animal models. Over the past decade, a genuine effort has been made to translate these results to humans under physiological conditions. Findings from in vivo human studies suggest that satellite cells play a key role in skeletal muscle fiber repair/remodeling in response to exercise. Mounting evidence indicates that aging has a profound impact on the regulation of satellite cells in human skeletal muscle. Yet, the precise role of satellite cells in the development of muscle fiber atrophy with age remains unresolved. This review seeks to integrate recent results from in vivo human studies on satellite cell function in muscle fiber repair/remodeling in the wider context of satellite cell biology whose literature is largely based on animal and cell models.

  17. [Terrorism and human behavior].

    Science.gov (United States)

    Leistedt, S J

    2017-06-09

    Theories of religion are essential for understanding current trends in terrorist activities. The aim of this work is to clarify religion's role in facilitating terror and outline in parallel with recent theoretical developments on terrorism and human behaviour. Several databases were used such as PubCentral, Scopus, Medline and Science Direct. The search terms "terrorism", "social psychology", "religion", "evolution", and "cognition" were used to identify relevant studies in the databases. This work examines, in a multidimensional way, how terrorists employ these features of religion to achieve their goals. In the same way, it describes how terrorists use rituals to conditionally associate emotions with sanctified symbols that are emotionally evocative and motivationally powerful, fostering group solidarity, trust, and cooperation. Religious beliefs, including promised rewards in the afterlife, further serve to facilitate cooperation by altering the perceived payoffs of costly actions, including suicide bombing. The adolescent pattern of brain development is unique, and young adulthood presents an ideal developmental stage to attract recruits and enlist them in high-risk behaviors. This work offers insights, based on this translational analysis, concerning the links between religion, terrorism and human behavior. Copyright © 2017 L'Encéphale, Paris. Published by Elsevier Masson SAS. All rights reserved.

  18. Behavioral plasticity through the modulation of switch neurons.

    Science.gov (United States)

    Vassiliades, Vassilis; Christodoulou, Chris

    2016-02-01

    A central question in artificial intelligence is how to design agents capable of switching between different behaviors in response to environmental changes. Taking inspiration from neuroscience, we address this problem by utilizing artificial neural networks (NNs) as agent controllers, and mechanisms such as neuromodulation and synaptic gating. The novel aspect of this work is the introduction of a type of artificial neuron we call "switch neuron". A switch neuron regulates the flow of information in NNs by selectively gating all but one of its incoming synaptic connections, effectively allowing only one signal to propagate forward. The allowed connection is determined by the switch neuron's level of modulatory activation which is affected by modulatory signals, such as signals that encode some information about the reward received by the agent. An important aspect of the switch neuron is that it can be used in appropriate "switch modules" in order to modulate other switch neurons. As we show, the introduction of the switch modules enables the creation of sequences of gating events. This is achieved through the design of a modulatory pathway capable of exploring in a principled manner all permutations of the connections arriving on the switch neurons. We test the model by presenting appropriate architectures in nonstationary binary association problems and T-maze tasks. The results show that for all tasks, the switch neuron architectures generate optimal adaptive behaviors, providing evidence that the switch neuron model could be a valuable tool in simulations where behavioral plasticity is required.

  19. The role of developmental plasticity and epigenetics in human health.

    Science.gov (United States)

    Gluckman, Peter D; Hanson, Mark A; Low, Felicia M

    2011-03-01

    Considerable epidemiological, experimental and clinical data have amassed showing that the risk of developing disease in later life is dependent on early life conditions, mainly operating within the normative range of developmental exposures. This relationship reflects plastic responses made by the developing organism as an evolved strategy to cope with immediate or predicted circumstances, to maximize fitness in the context of the range of environments potentially faced. There is now increasing evidence, both in animals and humans, that such developmental plasticity is mediated in part by epigenetic mechanisms. However, recognition of the importance of developmental plasticity as an important factor in influencing later life health-particularly within the medical and public health communities-is low, and we argue that this indifference cannot be sustained in light of the growing understanding of developmental processes and the rapid rise in the prevalence of obesity and metabolic disease globally. Copyright © 2011 Wiley-Liss, Inc.

  20. Engineered human dicentric chromosomes show centromere plasticity.

    Science.gov (United States)

    Higgins, Anne W; Gustashaw, Karen M; Willard, Huntington F

    2005-01-01

    The centromere is essential for the faithful distribution of a cell's genetic material to subsequent generations. Despite intense scrutiny, the precise genetic and epigenetic basis for centromere function is still unknown. Here, we have used engineered dicentric human chromosomes to investigate mammalian centromere structure and function. We describe three classes of dicentric chromosomes isolated in different cell lines: functionally monocentric chromosomes, in which one of the two genetically identical centromeres is consistently inactivated; functionally dicentric chromosomes, in which both centromeres are consistently active; and dicentric chromosomes heterogeneous with respect to centromere activity. A study of serial single cell clones from heterogeneous cell lines revealed that while centromere activity is usually clonal, the centromere state (i.e. functionally monocentric or dicentric) in some lines can switch within a growing population of cells. Because pulsed field gel analysis indicated that the DNA at the centromeres of these chromosomes did not change detectably, this switching of the centromere state is most likely due to epigenetic changes. Inactivation of one of the two active centromeres in a functionally dicentric chromosome was observed in a percentage of cells after treatment with Trichostatin A, an inhibitor of histone deacetylation. This study provides evidence that the activity of human centromeres, while largely stable, can be subject to dynamic change, most likely due to epigenetic modification.

  1. Mathematical models of human behavior

    DEFF Research Database (Denmark)

    Møllgaard, Anders Edsberg

    During the last 15 years there has been an explosion in human behavioral data caused by the emergence of cheap electronics and online platforms. This has spawned a whole new research field called computational social science, which has a quantitative approach to the study of human behavior. Most...... studies have considered data sets with just one behavioral variable such as email communication. The Social Fabric interdisciplinary research project is an attempt to collect a more complete data set on human behavior by providing 1000 smartphones with pre-installed data collection software to students...... data set, along with work on other behavioral data. The overall goal is to contribute to a quantitative understanding of human behavior using big data and mathematical models. Central to the thesis is the determination of the predictability of different human activities. Upper limits are derived...

  2. Mathematical models of human behavior

    DEFF Research Database (Denmark)

    Møllgaard, Anders Edsberg

    data set, along with work on other behavioral data. The overall goal is to contribute to a quantitative understanding of human behavior using big data and mathematical models. Central to the thesis is the determination of the predictability of different human activities. Upper limits are derived......, thereby implying that interactions between spreading processes are driving forces of attention dynamics. Overall, the thesis contributes to a quantitative understanding of a wide range of different human behaviors by applying mathematical modeling to behavioral data. There can be no doubt......During the last 15 years there has been an explosion in human behavioral data caused by the emergence of cheap electronics and online platforms. This has spawned a whole new research field called computational social science, which has a quantitative approach to the study of human behavior. Most...

  3. The Portuguese plastic carrier bag tax: The effects on consumers' behavior.

    Science.gov (United States)

    Martinho, Graça; Balaia, Natacha; Pires, Ana

    2017-03-01

    Marine litter from lightweight plastic bags is a global problem that must be solved. A plastic bag tax was implemented in February 2015 to reduce the consumption of plastic grocery bags in Portugal and in turn reduce the potential contribution to marine litter. This study analyzes the effect of the plastic bag tax on consumer behavior to learn how it was received and determine the perceived effectiveness of the tax 4months after its implementation. In addition, the study assessed how proximity to coastal areas could influence behaviors and opinions. The results showed a 74% reduction of plastic bag consumption with a simultaneously 61% increase of reusable plastic bags after the tax was implemented. Because plastic bags were then reused for shopping instead of garbage bags, however, the consumption of garbage bags increased by 12%. Although reduction was achieved, the tax had no effect on the perception of marine litter or the impact of plastic bags on environment and health. The majority of respondents agree with the tax but view it as an extra revenue to the State. The distance to the coast had no meaningful influence on consumer behavior or on the perception of the tax. Although the tax was able to promote the reduction of plastics, the role of hypermarkets and supermarkets in providing alternatives through the distribution of reusable plastic bags was determinant to ensuring the reduction.

  4. Use of polycarbonate plastic products and human health

    Directory of Open Access Journals (Sweden)

    R. K. Srivastava

    2013-02-01

    Full Text Available As plastic and plastic products are being used in day to day at the cost of environment pollution, the human and wild life health and has become a global concern. Researchers found link between abnormal liver enzymes in the people and Bisphenol-A (BPA. Changes in insulin resistance, reproduction system, cardiovascular and brain function are also reported. BPA is used in the production of epoxy resins, polycarbonate resins, and polyester resins. BPA can leach out of certain plastic products including variety of modern goods, reusable food storage containers, eyeglass lenses, white dental fillings, sealants, medical equipments etc. In the body, BPA behaves as an estrogen receptor agonist and mimics estrogen hormone. Bisphenol-A (BPA is a widespread endocrine-disrupting chemical (EDC used as the base compound in the manufacture of polycarbonate plastics. Children and unborn and new born babies are at high risk of unwanted effects of BPA. Children suffer from chronic exposure to bisphenol A with manifestation of gastrointestinal problems, adrenal stress, immune dysfunction, toxic over load and neurological disorders. Some study in Japan has observed that more BPA can leach from polycarbonate products that have been scratched or is more than 4 years old or used bottles that have been subjected to bottle brushing or dishwashing and sterilization. People exposed to higher levels of BPA due to use of plastic food and beverages containers are more likely to develop cardiovascular diseases, diabetes and metabolic disorder. Recent studies have suggested that BPA exposure may have a role in the development of weight gain, insulin resistance, pancreatic endocrine dysfunction, thyroid hormone disruption, and several other mechanisms involved in the development of diabetes. Urinary BPA levels are found to be associated with diabetes mellitus independent of traditional diabetes risk factors. There is a concern of exposure of BPA to pregnant women that can

  5. Training-induced behavioral and brain plasticity in inhibitory control

    Directory of Open Access Journals (Sweden)

    Lucas eSpierer

    2013-08-01

    Full Text Available Deficits in inhibitory control, the ability to suppress ongoing or planned motor or cognitive processes, contribute to many psychiatric and neurological disorders. The rehabilitation of inhibition-related disorders may therefore benefit from neuroplasticity-based training protocols aiming at normalizing inhibitory control proficiency and the underlying brain networks. Current literature on training-induced behavioral and brain plasticity in inhibitory control suggests that improvements may follow either from the development of automatic forms of inhibition or from the strengthening of top-down, controlled inhibition. Automatic inhibition develops in conditions of consistent and repeated associations between inhibition-triggering stimuli and stopping goals. Once established, the stop signals directly elicit inhibition, thereby bypassing slow, top-down executive control and accelerating stopping processes. In contrast, training regimens involving varying stimulus-response associations or frequent inhibition failures prevent the development of automatic inhibition and thus strengthen top-down inhibitory processes rather than bottom-up ones. We discuss these findings in terms of developing optimal inhibitory control training regimens for rehabilitation purposes.

  6. Single crystal plasticity by modeling dislocation density rate behavior

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Benjamin L [Los Alamos National Laboratory; Bronkhorst, Curt [Los Alamos National Laboratory; Beyerlein, Irene [Los Alamos National Laboratory; Cerreta, E. K. [Los Alamos National Laboratory; Dennis-Koller, Darcie [Los Alamos National Laboratory

    2010-12-23

    The goal of this work is to formulate a constitutive model for the deformation of metals over a wide range of strain rates. Damage and failure of materials frequently occurs at a variety of deformation rates within the same sample. The present state of the art in single crystal constitutive models relies on thermally-activated models which are believed to become less reliable for problems exceeding strain rates of 10{sup 4} s{sup -1}. This talk presents work in which we extend the applicability of the single crystal model to the strain rate region where dislocation drag is believed to dominate. The elastic model includes effects from volumetric change and pressure sensitive moduli. The plastic model transitions from the low-rate thermally-activated regime to the high-rate drag dominated regime. The direct use of dislocation density as a state parameter gives a measurable physical mechanism to strain hardening. Dislocation densities are separated according to type and given a systematic set of interactions rates adaptable by type. The form of the constitutive model is motivated by previously published dislocation dynamics work which articulated important behaviors unique to high-rate response in fcc systems. The proposed material model incorporates thermal coupling. The hardening model tracks the varying dislocation population with respect to each slip plane and computes the slip resistance based on those values. Comparisons can be made between the responses of single crystals and polycrystals at a variety of strain rates. The material model is fit to copper.

  7. Effect of Austempering on Plastic Behavior of Some Austempered Ductile Iron Alloys

    OpenAIRE

    Olofsson, Jakob; Larsson, Dan; Svensson, Ingvar L

    2011-01-01

    A numerical description relating microstructure to elastic and plastic deformation behavior would make it possible to simulate the mechanical behavior of complex cast components with tailored material properties. Limited work and data have however been published regarding the connection between microstructure and plastic behavior of austempered ductile irons (ADI). In the current work the effects of austempering temperature and austempering time on the strength coefficient and the strain hard...

  8. Plastic evolution behavior of H340LAD_Z steel by an optical method

    Science.gov (United States)

    Guo, Nan; Liang, Jin; Yu, Qiang; Qian, Boxing

    2017-02-01

    An optical method based on digital image correlation (DIC) technology was proposed to measure the plastic evolution of the high-strength low alloy steel H340LAD_Z. The basic principle of DIC technology is introduced, and then, the use of a 3D deformation measurement system and electronic universal testing machine to dynamically measure plastic evolution during the tensile yield stage is described. Through the full-field full-process measurement of plastic deformation during the yield stage in the 0°, 45° and 90° loading directions, the plastic evolution law was revealed. The results demonstrate that the proposed 3D DIC method can accurately reveal the starting and ending times for plastic evolution. The specimens in the three directions exhibit different plastic evolution behaviors, although they have similar yield strengths and yield times. The specimens in the 45° and 90° loading directions began to enter plastic deformation from bottom to top and the plastic area was maintained in a constant deformed state, while the evolution behavior in the 0° direction transited from both sides to the middle and plastic deformation was uneven. It is important to study plastic evolution of a metal sheet to determine the material properties and to provide an accurate basis for finite element modeling.

  9. Plastic evolution behavior of H340LAD-Z steel by an optical method

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Nan; Liang, Jin; Yu, Qiang; Qian, Boxing

    2017-02-01

    An optical method based on digital image correlation (DIC) technology was proposed to measure the plastic evolution of the high-strength low alloy steel H340LAD-Z. The basic principle of DIC technology is introduced, and then, the use of a 3D deformation measurement system and electronic universal testing machine to dynamically measure plastic evolution during the tensile yield stage is described. Through the full-field full-process measurement of plastic deformation during the yield stage in the 0°, 45° and 90° loading directions, the plastic evolution law was revealed. The results demonstrate that the proposed 3D DIC method can accurately reveal the starting and ending times for plastic evolution. The specimens in the three directions exhibit different plastic evolution behaviors, although they have similar yield strengths and yield times. The specimens in the 45° and 90° loading directions began to enter plastic deformation from bottom to top and the plastic area was maintained in a constant deformed state, while the evolution behavior in the 0° direction transited from both sides to the middle and plastic deformation was uneven. It is important to study plastic evolution of a metal sheet to determine the material properties and to provide an accurate basis for finite element modeling.

  10. RNA Directed Modulation of Phenotypic Plasticity in Human Cells.

    Science.gov (United States)

    Trakman, Laura; Hewson, Chris; Burdach, Jon; Morris, Kevin V

    2016-01-01

    Natural selective processes have been known to drive phenotypic plasticity, which is the emergence of different phenotypes from one genome following environmental stimulation. Long non-coding RNAs (lncRNAs) have been observed to modulate transcriptional and epigenetic states of genes in human cells. We surmised that lncRNAs are governors of phenotypic plasticity and drive natural selective processes through epigenetic modulation of gene expression. Using heat shocked human cells as a model we find several differentially expressed transcripts with the top candidates being lncRNAs derived from retro-elements. One particular retro-element derived transcripts, Retro-EIF2S2, was found to be abundantly over-expressed in heat shocked cells. Over-expression of Retro-EIF2S2 significantly enhanced cell viability and modulated a predisposition for an adherent cellular phenotype upon heat shock. Mechanistically, we find that this retro-element derived transcript interacts directly with a network of proteins including 40S ribosomal protein S30 (FAU), Eukaryotic translation initiation factor 5A (EIF5A), and Ubiquitin-60S ribosomal protein L40 (UBA52) to affect protein modulated cell adhesion pathways. We find one motif in Retro-EIF2S2 that exhibits binding to FAU and modulates phenotypic cell transitions from adherent to suspension states. The observations presented here suggest that retroviral derived transcripts actively modulate phenotypic plasticity in human cells in response to environmental selective pressures and suggest that natural selection may play out through the action of retro-elements in human cells.

  11. Plasticity of the human auditory cortex related to musical training.

    Science.gov (United States)

    Pantev, Christo; Herholz, Sibylle C

    2011-11-01

    During the last decades music neuroscience has become a rapidly growing field within the area of neuroscience. Music is particularly well suited for studying neuronal plasticity in the human brain because musical training is more complex and multimodal than most other daily life activities, and because prospective and professional musicians usually pursue the training with high and long-lasting commitment. Therefore, music has increasingly been used as a tool for the investigation of human cognition and its underlying brain mechanisms. Music relates to many brain functions like perception, action, cognition, emotion, learning and memory and therefore music is an ideal tool to investigate how the human brain is working and how different brain functions interact. Novel findings have been obtained in the field of induced cortical plasticity by musical training. The positive effects, which music in its various forms has in the healthy human brain are not only important in the framework of basic neuroscience, but they also will strongly affect the practices in neuro-rehabilitation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Behavioral plasticity is not signiifcantly associated withhead volume ina wild Chestnut Thrush (Turdus rubrocanus) population

    Institute of Scientific and Technical Information of China (English)

    Qingshan Zhao; Yuehua Sun

    2016-01-01

    Background: The drivers of intraspeciifc variation in behavioral plasticity are poorly known. A widely held hypothesis is that brain size is positively correlated with behavioral plasticity. Methods: A total of 71 Chestnut Thrushes (Turdus rubrocanus) were caught in the wild population. We quantiifed behavior plasticity of activity of individuals measured in the same cage across two contexts (common and with a novel object stimulation), using a random regression analysis. We then investigated whether head volume (a proxy for brain size) was associated with behavioral plasticity in activity level using Spearman rank-order correlation. Results: We found no signiifcant evidence that activity plasticity was associated with relative head volume. There was no sex difference in head volume or in variance in head volume. Conclusions: We speculate that the absence of an association between brain volume and activity behavior plasticity may result from the inaccuracy of using external skull measurements to estimate brain size, or from a particular part of the brain being responsible for plasticity in activity level.

  13. A reassessment of human cranial plasticity: Boas revisited.

    Science.gov (United States)

    Sparks, Corey S; Jantz, Richard L

    2002-11-12

    In 1912, Franz Boas published a study demonstrating the plastic nature of the human body in response to changes in the environment. The results of this study have been cited for the past 90 years as evidence of cranial plasticity. These findings, however, have never been critiqued thoroughly for their statistical and biological validity. This study presents a reassessment of Boas' data within a modern statistical and quantitative genetic framework. The data used here consist of head and face measurements on over 8,000 individuals of various European ethnic groups. By using pedigree information contained in Boas' data, narrow sense heritabilities are estimated by the method of maximum likelihood. In addition, a series of t tests and regression analyses are performed to determine the statistical validity of Boas' original findings on differentiation between American and European-born children and the prolonged effect of the environment on cranial form. Results indicate the relatively high genetic component of the head and face diameters despite the environmental differences during development. Results point to very small and insignificant differences between European- and American-born offspring, and no effect of exposure to the American environment on the cranial index in children. These results contradict Boas' original findings and demonstrate that they may no longer be used to support arguments of plasticity in cranial morphology.

  14. Musical training induces functional plasticity in human hippocampus.

    Science.gov (United States)

    Herdener, Marcus; Esposito, Fabrizio; di Salle, Francesco; Boller, Christian; Hilti, Caroline C; Habermeyer, Benedikt; Scheffler, Klaus; Wetzel, Stephan; Seifritz, Erich; Cattapan-Ludewig, Katja

    2010-01-27

    Training can change the functional and structural organization of the brain, and animal models demonstrate that the hippocampus formation is particularly susceptible to training-related neuroplasticity. In humans, however, direct evidence for functional plasticity of the adult hippocampus induced by training is still missing. Here, we used musicians' brains as a model to test for plastic capabilities of the adult human hippocampus. By using functional magnetic resonance imaging optimized for the investigation of auditory processing, we examined brain responses induced by temporal novelty in otherwise isochronous sound patterns in musicians and musical laypersons, since the hippocampus has been suggested previously to be crucially involved in various forms of novelty detection. In the first cross-sectional experiment, we identified enhanced neural responses to temporal novelty in the anterior left hippocampus of professional musicians, pointing to expertise-related differences in hippocampal processing. In the second experiment, we evaluated neural responses to acoustic temporal novelty in a longitudinal approach to disentangle training-related changes from predispositional factors. For this purpose, we examined an independent sample of music academy students before and after two semesters of intensive aural skills training. After this training period, hippocampal responses to temporal novelty in sounds were enhanced in musical students, and statistical interaction analysis of brain activity changes over time suggests training rather than predisposition effects. Thus, our results provide direct evidence for functional changes of the adult hippocampus in humans related to musical training.

  15. Irrational Human Behaviors

    Directory of Open Access Journals (Sweden)

    Orhan Şener

    2015-10-01

    Full Text Available Neo Classical economists used to posit that, since consumers are rational, they make decisions to maximize their pleasure (utility. Opposing to Neo Classical understanding, Behavioral Economists argue that, consumers are infect not rational, but prone to all sort of biases and habits that pull them being rational. For instance, there are too many irrational choices made by the Turkish consumers like; expensive wedding parties given by low income families; although riding bicycle is healthy and cheap, but people buy expensive cars; it is cheaper staying at a hotel or a timeshare, however people buy expensive summer houses, where they stayed only few weeks a year. These type of irrational behaviors adversely affect the decisions on savings, investments and economic growth. On the consumers irrationality, Tversky and Daniel Kahneman, winner of the 2002 Nobel Prize in Economics, wrote Prospect Theory. They developed a cognitive psychological model to explain divergences from neoclassical economics. They claimed that people take decisions under psychological, social, emotional and economic factors that affect market prices and resource allocation. In order to explain the irrational behaviors of Turkish consumers, I utilized some concepts such as conspicuous consumption (or keeping up with Johns, Veblen Effect, Bandwagon Effect, bounded rationality, 20 to 80 Law and ethical considerations developed by Behavioral Economists and Heterodox Economics. Thus, I came to conclusion that why the free market economic understanding fails in Turkey by giving some examples and economic reasons stated in the last section of this paper.

  16. Detection of Plastic Explosive Traces in the Human Thermal Plume

    Science.gov (United States)

    Gowadia, Huban A.; Settles, Gary S.

    1998-11-01

    Aviation security requires the detection of explosive devices which terrorists, posing as passengers, may conceal beneath their clothing. Our goal is to understand the generation, transport, and collection of trace signals from such concealed explosives, which are found in the natural convective plume produced by the human body. Previous work (APS/DFD96, CG10) has visualized this plume and shown that concealed volatile explosives (e.g. TNT) produce a detectable vapor signal therein. Plastic explosives, on the other hand, have vanishingly low vapor pressures and are thus considered very difficult to detect. Present experiments use a dispersal chamber to collect and sample the plumes of human subjects wearing concealed gauze patches containing milligrams of RDX, the primary component of plastic explosives such as C-4. These experiments address the effects of agitation, clothing, temperature and humidity on trace detectability. Further experiments address the effects of oily vs. dry skin, contaminated clothing vs. gauze patches, and residual contamination left on skin previously in contact with RDX. The key role of airborne contaminated textile fibers is noted. Knowledge thus gained contributes to the design of an explosive detection portal for aviation security screening. (Research supported by FAA Grant 93-G-052.)

  17. Animal models for human behavioral deficiencies during development.

    Science.gov (United States)

    Elsner, J

    1992-01-01

    Often considered to be a subdiscipline of neurotoxicology, experimental behavioral teratology has difficulties to be acknowledged by its own right. Results obtained in the laboratory concerning purely behavioral effects induced by low level prenatal exposure to substances are often doubted to contain any relevance with respect to humans. This doubt is based on many debates going on in the numerous extrapolation steps between observed effects on animal behavior and human psychopathology. Taking the inverse path, extrapolation from a typical human behavioral syndrome (minimal brain dysfunction) to observations which can be made on laboratory animals, the following main debates are discussed: the psychology debate (behaviorism--perceptionism--cognitivism); the psychopathology debate (hyperactivity--attention deficit--tactile-kinesthetic perception deficiency--sensory integration deficits); the relevance debate (behavior is reprogrammable software--behavioral deficits may reflect undetectable hardware defects); the interpretation debate (behavioral teratogenicity is chemical imprinting--behavioral disturbances due to chemicals reflect neurotoxicity); the intelligence debate (IQ decrements--attention deficits); the developmental delay debate (the relevance of a delay in the behavioral development); the sensitivity debate (behavior is the most sensitive measure in toxicology--the brain redundancy and plasticity compensates subtle deficiencies); the statistics debate (gather as many behavioral variables as possible--stay simple and measure only one aspect of behavior); the regulation debate (behavioral teratology should be regulated in detail--tests should not be prescribed). It is attempted to find rational solutions for these debates which menace to jeopardize the very existence of behavioral teratology.

  18. Increased morphological asymmetry, evolvability and plasticity in human brain evolution.

    Science.gov (United States)

    Gómez-Robles, Aida; Hopkins, William D; Sherwood, Chet C

    2013-06-22

    The study of hominin brain evolution relies mostly on evaluation of the endocranial morphology of fossil skulls. However, only some general features of external brain morphology are evident from endocasts, and many anatomical details can be difficult or impossible to examine. In this study, we use geometric morphometric techniques to evaluate inter- and intraspecific differences in cerebral morphology in a sample of in vivo magnetic resonance imaging scans of chimpanzees and humans, with special emphasis on the study of asymmetric variation. Our study reveals that chimpanzee-human differences in cerebral morphology are mainly symmetric; by contrast, there is continuity in asymmetric variation between species, with humans showing an increased range of variation. Moreover, asymmetric variation does not appear to be the result of allometric scaling at intraspecific levels, whereas symmetric changes exhibit very slight allometric effects within each species. Our results emphasize two key properties of brain evolution in the hominine clade: first, evolution of chimpanzee and human brains (and probably their last common ancestor and related species) is not strongly morphologically constrained, thus making their brains highly evolvable and responsive to selective pressures; second, chimpanzee and, especially, human brains show high levels of fluctuating asymmetry indicative of pronounced developmental plasticity. We infer that these two characteristics can have a role in human cognitive evolution.

  19. Thermal image analysis of plastic deformation and fracture behavior by a thermo-video measurement system

    Science.gov (United States)

    Ohbuchi, Yoshifumi; Sakamoto, Hidetoshi; Nagatomo, Nobuaki

    2016-12-01

    The visualization of the plastic region and the measurement of its size are necessary and indispensable to evaluate the deformation and fracture behavior of a material. In order to evaluate the plastic deformation and fracture behavior in a structural member with some flaws, the authors paid attention to the surface temperature which is generated by plastic strain energy. The visualization of the plastic deformation was developed by analyzing the relationship between the extension of the plastic deformation range and the surface temperature distribution, which was obtained by an infrared thermo-video system. Furthermore, FEM elasto-plastic analysis was carried out with the experiment, and the effectiveness of this non-contact measurement system of the plastic deformation and fracture process by a thermography system was discussed. The evaluation method using an infrared imaging device proposed in this research has a feature which does not exist in the current evaluation method, i.e. the heat distribution on the surface of the material has been measured widely by noncontact at 2D at high speed. The new measuring technique proposed here can measure the macroscopic plastic deformation distribution on the material surface widely and precisely as a 2D image, and at high speed, by calculation from the heat generation and the heat propagation distribution.

  20. Plastics, the environment and human health: current consensus and future trends

    OpenAIRE

    Richard C. Thompson; Moore, Charles J.; Frederick S Vom Saal; Swan, Shanna H.

    2009-01-01

    Plastics have transformed everyday life; usage is increasing and annual production is likely to exceed 300 million tonnes by 2010. In this concluding paper to the Theme Issue on Plastics, the Environment and Human Health, we synthesize current understanding of the benefits and concerns surrounding the use of plastics and look to future priorities, challenges and opportunities. It is evident that plastics bring many societal benefits and offer future technological and medical advances. However...

  1. Plastics, the environment and human health: current consensus and future trends

    OpenAIRE

    Thompson, Richard C.; Moore, Charles J.; vom Saal, Frederick S.; Swan, Shanna H.

    2009-01-01

    Plastics have transformed everyday life; usage is increasing and annual production is likely to exceed 300 million tonnes by 2010. In this concluding paper to the Theme Issue on Plastics, the Environment and Human Health, we synthesize current understanding of the benefits and concerns surrounding the use of plastics and look to future priorities, challenges and opportunities. It is evident that plastics bring many societal benefits and offer future technological and medical advances. However...

  2. Charges for plastic bags : Motivational and behavioral effects

    NARCIS (Netherlands)

    Jakovcevic, Adriana; Steg, Linda; Mazzeo, Nadia; Caballero, Romina; Franco, Paul; Putrino, Natalia; Favara, Jesica

    2014-01-01

    Two field studies tested the effects of a charge for single-use plastic bags recently implemented in Buenos Aires City, Argentina. Study 1 showed a greater increase in consumers' own bag use after the charge was introduced in supermarkets where the policy was introduced, in comparison to control sup

  3. Chronic alcohol exposure alters behavioral and synaptic plasticity of the rodent prefrontal cortex.

    Directory of Open Access Journals (Sweden)

    Sven Kroener

    Full Text Available In the present study, we used a mouse model of chronic intermittent ethanol (CIE exposure to examine how CIE alters the plasticity of the medial prefrontal cortex (mPFC. In acute slices obtained either immediately or 1-week after the last episode of alcohol exposure, voltage-clamp recording of excitatory post-synaptic currents (EPSCs in mPFC layer V pyramidal neurons revealed that CIE exposure resulted in an increase in the NMDA/AMPA current ratio. This increase appeared to result from a selective increase in the NMDA component of the EPSC. Consistent with this, Western blot analysis of the postsynaptic density fraction showed that while there was no change in expression of the AMPA GluR1 subunit, NMDA NR1 and NRB subunits were significantly increased in CIE exposed mice when examined immediately after the last episode of alcohol exposure. Unexpectedly, this increase in NR1 and NR2B was no longer observed after 1-week of withdrawal in spite of a persistent increase in synaptic NMDA currents. Analysis of spines on the basal dendrites of layer V neurons revealed that while the total density of spines was not altered, there was a selective increase in the density of mushroom-type spines following CIE exposure. Examination of NMDA-receptor mediated spike-timing-dependent plasticity (STDP showed that CIE exposure was associated with altered expression of long-term potentiation (LTP. Lastly, behavioral studies using an attentional set-shifting task that depends upon the mPFC for optimal performance revealed deficits in cognitive flexibility in CIE exposed mice when tested up to 1-week after the last episode of alcohol exposure. Taken together, these observations are consistent with those in human alcoholics showing protracted deficits in executive function, and suggest these deficits may be associated with alterations in synaptic plasticity in the mPFC.

  4. Molecular dynamics simulation of the plastic behavior anisotropy of shock-compressed monocrystal nickel

    Science.gov (United States)

    Chen, Ya-Zhou; Zhou, Liu-Cheng; He, Wei-Feng; Sun, Yu; Li, Ying-Hong; Jiao, Yang; Luo, Si-Hai

    2017-01-01

    Molecular dynamics simulations were used to study the plastic behavior of monocrystalline nickel under shock compression along the [100] and [110] orientations. The shock Hugoniot relation, local stress curve, and process of microstructure development were determined. Results showed the apparent anisotropic behavior of monocrystalline nickel under shock compression. The separation of elastic and plastic waves was also obvious. Plastic deformation was more severely altered along the [110] direction than the [100] direction. The main microstructure phase transformed from face-centered cubic to body-centered cubic and generated a large-scale and low-density stacking fault along the family of { 111 } crystal planes under shock compression along the [100] direction. By contrast, the main mechanism of plastic deformation in the [110] direction was the nucleation of the hexagonal, close-packed phase, which generated a high density of stacking faults along the [110] and [1̅10] directions.

  5. The Role of GluK4 in Synaptic Plasticity and Affective Behavior in Mice

    Science.gov (United States)

    Catches, Justin Samuel

    Kainate receptors (KARs) are glutamate-gated ion channels that signal through both ionotropic and metabotropic pathways (Contractor et al., 2011). Combinations of five KAR subunits (GluK1-5) form tetrameric receptors with GluK1, GluK2, and GluK3 able to form functional homomeric channels. The high-affinity subunits, GluK4 and GluK5, do not form homomeric channels but modify the properties of heteromeric receptors. Expression of the GluK4 receptor subunit in the forebrain is restricted to the CA3 region of the hippocampus and dentate gyrus regions where KARs modulate synaptic plasticity. In this study, ablation of Grik4, which encodes GluK4, in mice reduced KAR synaptic currents and altered activation properties of postsynaptic receptors but left two forms of presynaptic short-term plasticity intact. Disruption of both Grik4 and Grik5 caused complete loss of the postsynaptic ionotropic KAR current and impaired presynaptic frequency facilitation. Additionally, KAR surface expression was altered at pre- and postsynaptic sites at the MF synapse. Despite the loss of ionotropic signaling, KAR-mediated inhibition of the slow afterhyperpolarization current, which is dependent on metabotropic signaling, was intact in CA3 neurons. Long-term potentiation at the MF-CA3 synapse was reduced, likely through a loss of KAR modulation of excitability of the presynaptic MF axons. Genetic variants in the human GRIK4 gene alter the susceptibility for affective disorders (Bloss and Hunter, 2010). We found that ablation of Grik4 in mice resulted in reduced anxiety and an antidepressant-like phenotype. In the elevated zero-maze, a test for anxiety and risk taking behavior, and in two anxiogenic tests, marble-burying and novelty-induced suppression of feeding, anxiety-like behavior was consistently reduced in knockout animals. In the forced swim, a test of learned helplessness used to determine depression-like behavior, knockout mice demonstrated significantly less immobility suggesting

  6. Activin receptor signaling regulates cocaine-primed behavioral and morphological plasticity.

    Science.gov (United States)

    Gancarz, Amy M; Wang, Zi-Jun; Schroeder, Gabrielle L; Damez-Werno, Diane; Braunscheidel, Kevin M; Mueller, Lauren E; Humby, Monica S; Caccamise, Aaron; Martin, Jennifer A; Dietz, Karen C; Neve, Rachael L; Dietz, David M

    2015-07-01

    Activin receptor signaling, including the transcription factor Smad3, was upregulated in the rat nucleus accumbens (NAc) shell following withdrawal from cocaine. Direct genetic and pharmacological manipulations of this pathway bidirectionally altered cocaine seeking while governing morphological plasticity in NAc neurons. Thus, Activin/Smad3 signaling is induced following withdrawal from cocaine, and such regulation may be a key molecular mechanism underlying behavioral and cellular plasticity in the brain following cocaine self-administration.

  7. Human genomics and microarrays: implications for the plastic surgeon.

    Science.gov (United States)

    Cole, Jana; Isik, Frank

    2002-09-01

    The Human Genome Project was launched in 1989 in an effort to sequence the entire span of human DNA. Although coding sequences are important in identifying mutations, the static order of DNA does not explain how a cell or organism may respond to normal and abnormal biological processes. By examining the mRNA content of a cell, researchers can determine which genes are being activated in response to a stimulus. Traditional methods in molecular biology generally work on a "one gene: one experiment" basis, which means that the throughput is very limited and the "whole picture" of gene function is hard to obtain. To study each of the 60,000 to 80,000 genes in the human genome under each biological circumstance is not practical. Recently, microarrays (also known as gene or DNA chips) have emerged; these allow for the simultaneous determination of expression for thousands of genes and analysis of genome-wide mRNA expression. The purpose of this article is twofold: first, to provide the clinical plastic surgeon with a working knowledge and understanding of the fields of genomics, microarrays, and bioinformatics and second, to present a case to illustrate how these technologies can be applied in the study of wound healing.

  8. Evolution, development, and plasticity of the human brain: from molecules to bones

    Directory of Open Access Journals (Sweden)

    Branka eHrvoj-Mihic

    2013-10-01

    Full Text Available Neuroanatomical, molecular, and paleontological evidence is examined in light of human brain evolution. The brain of extant humans differs from the brains of other primates in its overall size and organization, and differences in size and organization of specific cortical areas and subcortical structures implicated into complex cognition and social and emotional processing. The human brain is also characterized by functional lateralizations, reflecting specializations of the cerebral hemispheres in humans for different types of processing, facilitating fast and reliable communication between neural cells in an enlarged brain. The features observed in the adult brain reflect human-specific patterns of brain development. Compared to the brains of other primates, the human brain takes longer to mature, promoting an extended period for establishing cortical microcircuitry and its modifications. Together, these features may underlie the prolonged period of learning and acquisition of technical and social skills necessary for survival, creating a unique cognitive and behavioral niche typical of our species.The neuroanatomical findings are in concordance with molecular analyses, which suggest a trend toward heterochrony in the expression of genes implicated in different functions. These include synaptogenesis, neuronal maturation and plasticity in humans, mutations in genes implicated in neurite outgrowth and plasticity, and an increased role of regulatory mechanisms, potentially promoting fast modification of neuronal morphologies in response to new computational demands. At the same time, endocranial casts of fossil hominins provide an insight into the timing of the emergence of uniquely human features in the course of evolution. We conclude by proposing several ways of combining comparative neuroanatomy, molecular biology and insights gained from fossil endocasts in future research.

  9. Evolution, development, and plasticity of the human brain: from molecules to bones.

    Science.gov (United States)

    Hrvoj-Mihic, Branka; Bienvenu, Thibault; Stefanacci, Lisa; Muotri, Alysson R; Semendeferi, Katerina

    2013-10-30

    Neuroanatomical, molecular, and paleontological evidence is examined in light of human brain evolution. The brain of extant humans differs from the brains of other primates in its overall size and organization, and differences in size and organization of specific cortical areas and subcortical structures implicated into complex cognition and social and emotional processing. The human brain is also characterized by functional lateralizations, reflecting specializations of the cerebral hemispheres in humans for different types of processing, facilitating fast and reliable communication between neural cells in an enlarged brain. The features observed in the adult brain reflect human-specific patterns of brain development. Compared to the brains of other primates, the human brain takes longer to mature, promoting an extended period for establishing cortical microcircuitry and its modifications. Together, these features may underlie the prolonged period of learning and acquisition of technical and social skills necessary for survival, creating a unique cognitive and behavioral niche typical of our species. The neuroanatomical findings are in concordance with molecular analyses, which suggest a trend toward heterochrony in the expression of genes implicated in different functions. These include synaptogenesis, neuronal maturation, and plasticity in humans, mutations in genes implicated in neurite outgrowth and plasticity, and an increased role of regulatory mechanisms, potentially promoting fast modification of neuronal morphologies in response to new computational demands. At the same time, endocranial casts of fossil hominins provide an insight into the timing of the emergence of uniquely human features in the course of evolution. We conclude by proposing several ways of combining comparative neuroanatomy, molecular biology and insights gained from fossil endocasts in future research.

  10. Viscous-elastic-plastic behavior of bone using Berkovich nanoindentation

    Science.gov (United States)

    Olesiak, Sara E.; Oyen, Michelle L.; Ferguson, Virginia L.

    2010-05-01

    A series viscous-elastic-plastic (VEP) indentation model was expanded to include analysis of the common trapezoidal testing condition, consisting of constant loading—and unloading—rates with an intervening creep hold period. This full VEP model was applied to analyze nanoindentation test of three polymers and five different types of bone. The full VEP solution allows for direct determination of the viscous term as calculated from the creep hold, while the elastic and plastic material parameters were determined from a non-linear curve-fit of the unloading displacement-time data. Additionally, the use of the trapezoidal loading procedure permitted analysis of the unloading load-displacement data with traditional Oliver-Pharr analysis; the material properties from this analysis compared well with those obtained with VEP analysis. Using the full VEP solution and fitted material constants the loading and creep hold displacement-time curves were simulated and matched well to both polymer and bone experimental data. The full VEP solution shows great promise in for obtaining material parameters for many viscoelastic materials such as hydrated bone, polymers, and other biological tissues.

  11. Influence of plasticizer content on the transition of electromechanical behavior of PVC gel actuator.

    Science.gov (United States)

    Ali, Mohammad; Ueki, Takamitsu; Tsurumi, Daijiro; Hirai, Toshihiro

    2011-06-21

    The actuation performance of plasticized poly(vinyl chloride) (PVC) gel actuators in an electric field depends on their chemical composition and electrical and mechanical properties. The influence of plasticizer (dibutyl adipate) content on electromechanical behavior of PVC gels was investigated by impedance spectroscopy and space charge measurement. By plasticizing the PVC, the dielectric constant and space charge density of PVC gel were drastically increased at 1:2 w/w ratio of PVC to plasticizer. To apply the results obtained from the impedance spectroscopy and space charge measurement, electrostatic adhesive forces generated between the PVC gel and the anode were measured. The electrostatic adhesive force at the anode was also dramatically increased at the same plasticizer content. All of the results indicated a transition of electromechanical behavior of PVC gel in the electric field, which was considered to originate from the orientation of polarized plasticizer molecules and dipole rotation of PVC chains. By using the electrostatic adhesive force of PVC gel derived from the electromechanical transition, a new electroactive actuator can be developed for novel applications.

  12. Energy dissipation and contour integral characterizing fracture behavior of incremental plasticity

    Institute of Scientific and Technical Information of China (English)

    Qi-Lin He; Lin-Zhi Wu; Ming Li; Hong-Bo Chen

    2011-01-01

    Jep-integral is derived for characterizing the fracture behavior of elastic-plastic materials. The Jep-integral differs from Rice's J-integral in that the free energy density rather than the stress working density is employed to define energy-momentum tensor. The Jep-integral is proved to be path-dependent regardless of incremental plasticity and deformation plasticity. The Jep-integral possesses clearly clear physical meaning: (1) the value Jeptjp evaluated on the infinitely small contour surrounding the crack tip represents the crack tip energy dissipation; (2) when the global steadystate crack growth condition is approached, the value of Jepfar-ss calculated along the boundary contour equals to the sum of crack tip dissipation and bulk dissipation of plastic zone. The theoretical results are verified by simulating mode I crack problems.

  13. Effect of Austempering on Plastic Behavior of Some Austempered Ductile Iron Alloys

    Science.gov (United States)

    Olofsson, Jakob; Larsson, Dan; Svensson, Ingvar L.

    2011-12-01

    A numerical description relating microstructure to elastic and plastic deformation behavior would make it possible to simulate the mechanical behavior of complex cast components with tailored material properties. Limited work and data, however, have been published regarding the connection between microstructure and plastic behavior of austempered ductile irons (ADIs). In the current work, the effects of austempering temperature and austempering time on the strength coefficient and the strain hardening exponent of the Hollomon equation were investigated for two ADI alloys. The results show that the plastic behavior is highly dependent on the combination of austempering temperature and austempering time. It was found that as the austempering temperature increases, both the strength coefficient and the strain hardening exponent initially decrease, but after reaching a minimum at the critical austempering temperature, they show a plateau or an increase. The effect of the austempering time on the plastic behavior depends on the austempering temperature. At low austempering temperatures, the strength coefficient and the strain hardening exponent decrease with increased austempering time, whereas at higher austempering temperatures, they show little time dependence. These relations are explained by the microstructural transformations that take place during the austempering heat treatment.

  14. Healing behavior of preexisting hydrogen micropores in aluminum alloys during plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Toda, H., E-mail: toda@pse.tut.ac.jp [Department of Production Systems Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Minami, K. [Department of Production Systems Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Koyama, K.; Ichitani, K. [Furukawa-Sky Aluminum Corp., 1351, Uwanodai, Fukaya, Saitama 366-8511 (Japan); Kobayashi, M. [Department of Production Systems Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Uesugi, K.; Suzuki, Y. [Japan Synchrotron Radiation Research Institute, Mikazuki-cho, Sayo-gun, Hyogo 679-5198 (Japan)

    2009-09-15

    Synchrotron X-ray microtomography was used to observe the shrinkage and annihilation behaviors of hydrogen micropores in three dimensions during hot and cold plastic deformation of an Al-Mg alloy. Whether complete healing of micropores is achieved after plastic deformation was examined by exposing the material to a high temperature after plastic deformation. Although micropores generally show a pattern of shrinking and closing, closer inspection of a single specimen revealed a variety of geometrically variable behaviors. It is noteworthy that some of the micropores are reinitiated in positions identical to those before their annihilation, even after an 8-22% macroscopic strain has been further applied after annihilation. We attribute local variations such as these to significant local strain variation, which we measured in a series of tomographic volumes by tracking the microstructural features.

  15. Plasticity of the human otolith-ocular reflex

    Science.gov (United States)

    Wall, C. 3rd; Smith, T. R.; Furman, J. M.

    1992-01-01

    The eye movement response to earth vertical axis rotation in the dark, a semicircular canal stimulus, can be altered by prior exposure to combined visual-vestibular stimuli. Such plasticity of the vestibulo-ocular reflex has not been described for earth horizontal axis rotation, a dynamic otolith stimulus. Twenty normal human subjects underwent one of two types of adaptation paradigms designed either to attenuate or enhance the gain of the semicircular canal-ocular reflex prior to undergoing otolith-ocular reflex testing with horizontal axis rotation. The adaptation paradigm paired a 0.2 Hz sinusoidal rotation about a vertical axis with a 0.2 Hz optokinetic stripe pattern that was deliberately mismatched in peak velocity. Pre- and post-adaptation horizontal axis rotations were at 60 degrees/s in the dark and produced a modulation in the slow component velocity of nystagmus having a frequency of 0.17 Hz due to putative stimulation of the otolith organs. Results showed that the magnitude of this modulation component response was altered in a manner similar to the alteration in semicircular canal-ocular responses. These results suggest that physiologic alteration of the vestibulo-ocular reflex using deliberately mismatched visual and semicircular canal stimuli induces changes in both canal-ocular and otolith-ocular responses. We postulate, therefore, that central nervous system pathways responsible for controlling the gains of canal-ocular and otolith-ocular reflexes are shared.

  16. Mechanical and time-dependent behavior of wood-plastic composites subjected to tension and compression

    Science.gov (United States)

    Scott E. Hamel; John C. Hermanson; Steven M. Cramer

    2012-01-01

    The thermoplastics within wood—plastic composites (WPCs) are known to experience significant time-dependent deformation or creep. In some formulations, creep deformation can be twice as much as the initial quasi-static strain in as little as 4 days. While extensive work has been done on the creep behavior of pure polymers, little information is available on the...

  17. Sensory and motor components of reproductive behavior : pathways and plasticity

    NARCIS (Netherlands)

    Holstege, Gert; Van der Horst, Veronique G.J.M.

    Reproductive behavior in most mammalian species consists of a highly stereotyped pattern of movements, is elicited by specific sensory stimuli and is sex steroid dependent. The present paper describes a concept of the pathways in the midbrain, brainstem and spinal cord which control the receptive

  18. Experimental investigation and numerical simulation of plastic flow behavior during forward-backward-radial extrusion process

    OpenAIRE

    A. Farhoumand; R. Ebrahimi

    2016-01-01

    Finite element method was employed to investigate the effect of process parameters of plastic deformation behavior in Forward-Backward-Radial Extrusion (FBRE) process. The result of an axisymmetric model shows that the friction between die components and the sample has a substantial effect on the material flow behavior. Although strain heterogeneity index (SHI) slightly decreases with an increase in friction, large portion of the sample experiences significant strain heterogeneity. Increasing...

  19. Diversity in human behavioral ecology.

    Science.gov (United States)

    Hames, Raymond

    2014-12-01

    As befitting an evolutionary approach to the study of human behavior, the papers in this special issue of Human Nature cover a diversity of topics in modern and traditional societies. They include the goals of hunting in foraging societies, social bias, cooperative breeding, the impact of war on women, leadership, and social mobility. In combination these contributions demonstrate the utility of selectionist's thinking on a wide variety of topics. While many of the contributions employ standard evolutionary biological approaches such as kin selection, cooperative breeding and the Trivers-Willard model, others examine important human issues such as the problems of trust, the cost of war to women, the characteristics of leaders, and what might be called honest or rule-bound fights. One striking feature of many of the contributions is a novel reexamination of traditional research questions from an evolutionary perspective.

  20. Nonlinear dynamics in human behavior

    Energy Technology Data Exchange (ETDEWEB)

    Huys, Raoul [Centre National de la Recherche Scientifique (CNRS), 13 - Marseille (France); Marseille Univ. (France). Movement Science Inst.; Jirsa, Viktor K. (eds.) [Centre National de la Recherche Scientifique (CNRS), 13 - Marseille (France); Marseille Univ. (France). Movement Science Inst.; Florida Atlantic Univ., Boca Raton, FL (United States). Center for Complex Systems and Brain Sciences

    2010-07-01

    Humans engage in a seemingly endless variety of different behaviors, of which some are found across species, while others are conceived of as typically human. Most generally, behavior comes about through the interplay of various constraints - informational, mechanical, neural, metabolic, and so on - operating at multiple scales in space and time. Over the years, consensus has grown in the research community that, rather than investigating behavior only from bottom up, it may be also well understood in terms of concepts and laws on the phenomenological level. Such top down approach is rooted in theories of synergetics and self-organization using tools from nonlinear dynamics. The present compendium brings together scientists from all over the world that have contributed to the development of their respective fields departing from this background. It provides an introduction to deterministic as well as stochastic dynamical systems and contains applications to motor control and coordination, visual perception and illusion, as well as auditory perception in the context of speech and music. (orig.)

  1. Organophosphorus flame retardants and plasticizers: sources, occurrence, toxicity and human exposure.

    Science.gov (United States)

    Wei, Gao-Ling; Li, Ding-Qiang; Zhuo, Mu-Ning; Liao, Yi-Shan; Xie, Zhen-Yue; Guo, Tai-Long; Li, Jun-Jie; Zhang, Si-Yi; Liang, Zhi-Quan

    2015-01-01

    Due to the restricted use and ban of brominated flame retardants, organophosphorus compounds (OPs), extensively used as flame retardants and plasticizers, are ubiquitous in various environmental compartments worldwide. The present study shows that the release of OPs from a wide variety of commercial products and wastewater discharge might be considered as primary emission sources and that high potential of long-range atmospheric transport and persistence of OPs would be responsible for their presence in various matrices on a global scale. The occurrence and environmental behaviors of OPs in diverse matrices (e.g., dust, air, water, sediment, soil and biota) are reviewed. Human exposures to OPs via dermal contact, dust ingestion, inhalation and dietary intake are comprehensively evaluated. Finally, this study identifies gaps in the existing issues and generates a future agenda for the emerging contaminants OPs.

  2. On our best behavior: optimality models in human behavioral ecology.

    Science.gov (United States)

    Driscoll, Catherine

    2009-06-01

    This paper discusses problems associated with the use of optimality models in human behavioral ecology. Optimality models are used in both human and non-human animal behavioral ecology to test hypotheses about the conditions generating and maintaining behavioral strategies in populations via natural selection. The way optimality models are currently used in behavioral ecology faces significant problems, which are exacerbated by employing the so-called 'phenotypic gambit': that is, the bet that the psychological and inheritance mechanisms responsible for behavioral strategies will be straightforward. I argue that each of several different possible ways we might interpret how optimality models are being used for humans face similar and additional problems. I suggest some ways in which human behavioral ecologists might adjust how they employ optimality models; in particular, I urge the abandonment of the phenotypic gambit in the human case.

  3. Neural plasticity in hypocretin neurons: the basis of hypocretinergic regulation of physiological and behavioral functions in animals

    Directory of Open Access Journals (Sweden)

    Xiao-Bing eGao

    2015-10-01

    Full Text Available The neuronal system that resides in the perifornical and lateral hypothalamus (Pf/LH and synthesizes the neuropeptide hypocretin/orexin participates in critical brain functions across species from fish to human. The hypocretin system regulates neural activity responsible for daily functions (such as sleep/wake homeostasis, energy balance, appetite, etc and long-term behavioral changes (such as reward seeking and addiction, stress response, etc in animals. The most recent evidence suggests that the hypocretin system undergoes substantial plastic changes in response to both daily fluctuations (such as food intake and sleep-wake regulation and long-term changes (such as cocaine seeking in neuronal activity in the brain. The understanding of these changes in the hypocretin system is essential in addressing the role of the hypocretin system in normal physiological functions and pathological conditions in animals and humans. In this review, the evidence demonstrating that neural plasticity occurs in hypocretin-containing neurons in the Pf/LH will be presented and possible physiological behavioral, and mental health implications of these findings will be discussed.

  4. Elastic-plastic behavior of a semicircular frame being pressed against a rigid plane

    Institute of Scientific and Technical Information of China (English)

    X. W. Zhang; J. L. Yang; T. X. Yu

    2008-01-01

    As a simplified structural model, a semicircular frame is used to study the crashworthiness behavior of an aircraft fuselage. The quasi-static large elastic-plastic deformation of a semicircular frame in the process of its being pressed against a rigid ground is analyzed. First, based on the linear elastic assumption, the quasi-static large deformation contact process of the frame can be divided into three phases, i.e., point contact, line contact and post-buckling. By means of a shooting method, the relations between the displacement and contact force as well as the distribution of bending moment in the three phases are obtained. Then, by assuming an elastic, perfectly-plastic moment-curvature relationship for the semi-circular frame, the contact process is analyzed in detail to reveal the plastic collapse mechanism, the traveling of plastic hinge and the force-displacement relationship. In order to verify the analysis, a preliminary experiment was conducted, in which two types of half rings with clamped ends were pressed by a rigid plate. In addition, a numerical simulation is also conducted by employing ABAQUS to analyze both rectangular cross-sectional beam and I-beam. Finally, the theoretical predictions are compared with the experimental results and numerical solutions, showing that the elastic-plastic analysis can predict the contact process very well.

  5. Improved histochemical methods for the examination of plastic-embedded human marrow

    Energy Technology Data Exchange (ETDEWEB)

    Moosavi, H.; Lichtman, M. A.; Donnelly, J. A.; Churukian, C. J.

    1979-01-01

    Improved methods for processing, sectioning, and staining plastic (glycol methacrylate) embedded human marrow biopsies are described. Marrow biopsies processed by this technique were compared with biopsies processed by the conventional paraffin embedding method. The plastic-embedded marrows provide better morphology enhancing diagnostic accuracy, permit assessment of bone as well as marrow, and allow histochemical analysis of biopsy specimen. Special stains including naphtol AS-D chloroacetate esterase, periodic acid Schiff (PAS), reticulin, and iron have been modified so that they are suitable for undecalcified, two microns thick, plastic-embedded human marrow biopsies.

  6. Why New Spinal Cord Plasticity Does Not Disrupt Old Motor Behaviors.

    Science.gov (United States)

    Chen, Yi; Chen, Lu; Wang, Yu; Chen, Xiang Yang; Wolpaw, Jonathan R

    2017-08-23

    When new motor learning changes the spinal cord, old behaviors are not impaired; their key features are preserved by additional compensatory plasticity. To explore the mechanisms responsible for this compensatory plasticity, we transected the spinal dorsal ascending tract before or after female rats acquired a new behavior-operantly conditioned increase or decrease in the right soleus H-reflex-and examined an old behavior-locomotion. Neither spinal dorsal ascending tract transection nor H-reflex conditioning alone impaired locomotion. Nevertheless, when spinal dorsal ascending tract transection and H-reflex conditioning were combined, the rats developed a limp and a tilted posture that correlated in direction and magnitude with the H-reflex change. When the right H-reflex was increased by conditioning, the right step lasted longer than the left and the right hip was higher than the left; when the right H-reflex was decreased by conditioning, the opposite occurred. These results indicate that ascending sensory input guides the compensatory plasticity that normally prevents the plasticity underlying H-reflex change from impairing locomotion. They support the concept of the state of the spinal cord as a negotiated equilibrium that reflects the concurrent influences of all the behaviors in an individual's repertoire; and they support the new therapeutic strategies this concept introduces.SIGNIFICANCE STATEMENT The spinal cord provides a reliable final common pathway for motor behaviors throughout life. Until recently, its reliability was explained by the assumption that it is hardwired; but it is now clear that the spinal cord changes continually as new behaviors are acquired. Nevertheless, old behaviors are preserved. This study shows that their preservation depends on sensory feedback from the spinal cord to the brain: if feedback is removed, the acquisition of a new behavior may disrupt an old behavior. In sum, when a new behavior changes the spinal cord, sensory

  7. Leaching of the plasticizer di(2-ethylhexyl)phthalate (DEHP) from plastic containers and the question of human exposure.

    Science.gov (United States)

    Erythropel, Hanno C; Maric, Milan; Nicell, Jim A; Leask, Richard L; Yargeau, Viviane

    2014-12-01

    Di(2-ethylhexyl)phthalate (DEHP) is a widely used plasticizer to render poly(vinyl chloride) (PVC) soft and malleable. Plasticized PVC is used in hospital equipment, food wrapping, and numerous other commercial and industrial products. Unfortunately, plasticizers can migrate within the material and leach out of it over time, ending up in the environment and, frequently, the human body. DEHP has come under increased scrutiny as its breakdown products are believed to be endocrine disruptors and more toxic than DEHP itself. DEHP and its breakdown products have been identified as ubiquitous environmental contaminants, and daily human exposure is estimated to be in the microgram per kilogram level. The objective of this review is to summarize and comment on published sources of DEHP exposure and to give an overview of its environmental fate. Exposure through bottled water was examined specifically, as this concern is raised frequently, yet only little exposure to DEHP occurs through bottled water, and DEHP exposure is unlikely to stem from the packaging material itself. Packaged food was also examined and showed higher levels of DEHP contamination compared to bottled water. Exposure to DEHP also occurs in hospital environments, where DEHP leaches directly into liquids that passed through PVC/DEHP tubing and equipment. The latter exposure is at considerably higher levels compared to food and bottled water, specifically putting patients with chronic illnesses at risk. Overall, levels of DEHP in food and bottled water were below current tolerable daily intake (TDI) values. However, our understanding of the risks of DEHP exposure is still evolving. Given the prevalence of DEHP in our atmosphere and environment, and the uncertainty revolving around it, the precautionary principle would suggest its phaseout and replacement. Increased efforts to develop viable replacement compounds, which necessarily includes rigorous leaching, toxicity, and impact assessment studies, are

  8. Biodegradable plastics from Sinorhizobium meliloti as plastics compatible with the environment and human health

    Directory of Open Access Journals (Sweden)

    Mehrdad Hashemi Beidokhti

    2016-03-01

    Full Text Available Introduction: Polyhydroxyalkanoates (PHAs are natural polyesters and biodegradable plastics that are stored as intracellular inclusion bodies by a great variety of bacteria. The aim of this study was to extract polyhydroxyalkanoate from native Sinorhizobium meliloti in Iran. Materials and methods: Sinorhizobium meliloti isolates were collected from roots of alfalfa plants and were identified by Gram staining, biochemical experiments and amplification of 1500 bp fragment of 16Sr DNA gene. PHA granules were detected by microscopic examination. PHA production was evaluated in nutrient deficient medium and its amount was determined by conversion of PHA into crotonic acid by sulphuric acid treatment. The effect of various temperatures, agitation rate and carbon source (sucrose, mannitol, and maltose were evaluated on dry cell weight and polyhydroxybutyrate (PHB production. Results: The maximum amount of polymer production (43.10% was seen in basal mineral medium at 29°C, pH~7 and 215 revolutions per minute (rpm. The results of this research showed that the S5 isolate was capable to produce maximum poly3- hydroxybutyrate. The produced polymer was analyzed for its purity by GC- mass (gas chromatography- mass spectroscopy and confirmed to be PHB compared with the standard polymer. Discussion and conclusion: Native strains of Sinorhizobium can be used in the production of biodegradable plastics and the results of present study showed that S. meliloti S5 was capable to produce maximum PHB at 29°C, agitation rate of 215 rpm, and pH~7. 

  9. Dosage-dependent effect of dopamine D2 receptor activation on motor cortex plasticity in humans.

    Science.gov (United States)

    Fresnoza, Shane; Stiksrud, Elisabeth; Klinker, Florian; Liebetanz, David; Paulus, Walter; Kuo, Min-Fang; Nitsche, Michael A

    2014-08-06

    The neuromodulator dopamine plays an important role in synaptic plasticity. The effects depend on receptor subtypes, affinity, concentration level, and the kind of neuroplasticity induced. In animal experiments, dopamine D2-like receptor stimulation revealed partially antagonistic effects on plasticity, which might be explained by dosage dependency. In humans, D2 receptor block abolishes plasticity, and the D2/D3, but predominantly D3, receptor agonist ropinirol has a dosage-dependent nonlinear affect on plasticity. Here we aimed to determine the specific affect of D2 receptor activation on neuroplasticity in humans, because physiological effects of D2 and D3 receptors might differ. Therefore, we combined application of the selective D2 receptor agonist bromocriptine (2.5, 10, and 20 mg or placebo medication) with anodal and cathodal transcranial direct current stimulation (tDCS), which induces nonfocal plasticity, and with paired associative stimulation (PAS) generating a more focal kind of plasticity in the motor cortex of healthy humans. Plasticity was monitored by transcranial magnetic stimulation-induced motor-evoked potential amplitudes. For facilitatory tDCS, bromocriptine prevented plasticity induction independent from drug dosage. However, its application resulted in an inverted U-shaped dose-response curve on inhibitory tDCS, excitability-diminishing PAS, and to a minor degree on excitability-enhancing PAS. These data support the assumption that modulation of D2-like receptor activity exerts a nonlinear dose-dependent effect on neuroplasticity in the human motor cortex that differs from predominantly D3 receptor activation and that the kind of plasticity-induction procedure is relevant for its specific impact.

  10. Nutrient mediation of behavioral plasticity and resource allocation in a xylem-feeding leafhopper.

    Science.gov (United States)

    Brodbeck, Brent V; Andersen, Peter C; Mizell, Russell F

    2011-01-01

    Phenotypic plasticity may be critical for nutrient-limited organisms that allocate ingested nutrients to the competing demands of reproduction and survivorship. Leafhoppers that feed on xylem fluid allow assessment of plasticity in response to the constant selective pressure of nutritional inadequacy. We examined feeding behavior (host selection and consumption rates) and nutrient allocation (fecundity, change in body mass and composition) of the xylem fluid-feeding leafhopper Homalodisca vitripennis (Hemiptera:Cicadellidae) on ten genotypes of related Prunus germplasm when adults first seasonally appear, and later during population peaks, to examine the effects of genotypes and season on plasticity of life history and behavioral traits. Behavior and resource allocation to life history traits were both mediated by xylem nutrients, although nutrients impacting behavior differed from those mediating life history. Host selection and consumption varied with genotype between June and July, yet behavior consistently reflected concentrations of dietary glutamine. Resource allocations also increased linearly with nutrient concentrations, but were best correlated to ingested essential amino acids rather than glutamine. Body mass and composition were highly correlated to dietary essential amino acids in June; 6 weeks later, fecundity was instead proportional to essential amino acids. The discrepancy in nutrients which impact behavior versus those mediating life history may explain the weak preference-performance linkage documented for many insects. The demarcation in allocating resources to biomass in June to fecundity in July suggests increased allocation to reproduction during periods of nutrient stress as predicted by the theory of optimal resource allocation; other contributing biotic and abiotic factors are also discussed.

  11. Plastics, the environment and human health: current consensus and future trends.

    Science.gov (United States)

    Thompson, Richard C; Moore, Charles J; vom Saal, Frederick S; Swan, Shanna H

    2009-07-27

    Plastics have transformed everyday life; usage is increasing and annual production is likely to exceed 300 million tonnes by 2010. In this concluding paper to the Theme Issue on Plastics, the Environment and Human Health, we synthesize current understanding of the benefits and concerns surrounding the use of plastics and look to future priorities, challenges and opportunities. It is evident that plastics bring many societal benefits and offer future technological and medical advances. However, concerns about usage and disposal are diverse and include accumulation of waste in landfills and in natural habitats, physical problems for wildlife resulting from ingestion or entanglement in plastic, the leaching of chemicals from plastic products and the potential for plastics to transfer chemicals to wildlife and humans. However, perhaps the most important overriding concern, which is implicit throughout this volume, is that our current usage is not sustainable. Around 4 per cent of world oil production is used as a feedstock to make plastics and a similar amount is used as energy in the process. Yet over a third of current production is used to make items of packaging, which are then rapidly discarded. Given our declining reserves of fossil fuels, and finite capacity for disposal of waste to landfill, this linear use of hydrocarbons, via packaging and other short-lived applications of plastic, is simply not sustainable. There are solutions, including material reduction, design for end-of-life recyclability, increased recycling capacity, development of bio-based feedstocks, strategies to reduce littering, the application of green chemistry life-cycle analyses and revised risk assessment approaches. Such measures will be most effective through the combined actions of the public, industry, scientists and policymakers. There is some urgency, as the quantity of plastics produced in the first 10 years of the current century is likely to approach the quantity produced in the

  12. Plastics, the environment and human health: current consensus and future trends

    Science.gov (United States)

    Thompson, Richard C.; Moore, Charles J.; vom Saal, Frederick S.; Swan, Shanna H.

    2009-01-01

    Plastics have transformed everyday life; usage is increasing and annual production is likely to exceed 300 million tonnes by 2010. In this concluding paper to the Theme Issue on Plastics, the Environment and Human Health, we synthesize current understanding of the benefits and concerns surrounding the use of plastics and look to future priorities, challenges and opportunities. It is evident that plastics bring many societal benefits and offer future technological and medical advances. However, concerns about usage and disposal are diverse and include accumulation of waste in landfills and in natural habitats, physical problems for wildlife resulting from ingestion or entanglement in plastic, the leaching of chemicals from plastic products and the potential for plastics to transfer chemicals to wildlife and humans. However, perhaps the most important overriding concern, which is implicit throughout this volume, is that our current usage is not sustainable. Around 4 per cent of world oil production is used as a feedstock to make plastics and a similar amount is used as energy in the process. Yet over a third of current production is used to make items of packaging, which are then rapidly discarded. Given our declining reserves of fossil fuels, and finite capacity for disposal of waste to landfill, this linear use of hydrocarbons, via packaging and other short-lived applications of plastic, is simply not sustainable. There are solutions, including material reduction, design for end-of-life recyclability, increased recycling capacity, development of bio-based feedstocks, strategies to reduce littering, the application of green chemistry life-cycle analyses and revised risk assessment approaches. Such measures will be most effective through the combined actions of the public, industry, scientists and policymakers. There is some urgency, as the quantity of plastics produced in the first 10 years of the current century is likely to approach the quantity produced in the

  13. THE SIGNIFICANCE OF THE SUBPLATE FOR EVOLUTION AND DEVELOPMENTAL PLASTICITY OF THE HUMAN BRAIN

    Directory of Open Access Journals (Sweden)

    MILOS eJUDAS

    2013-08-01

    Full Text Available The human life-history is characterized by long development and introduction of new developmental stages, such as childhood and adolescence. The developing brain had important role in these life-history changes because it is expensive tissue which uses up to 80% of resting metabolic rate in the newborn and continues to use almost 50% of it during the first 5 postnatal years. Our hominid ancestors managed to lift-up metabolic constraints to increase in brain size by several interrelated ecological, behavioral and social adaptations, such as dietary change, invention of cooking, creation of family-bonded reproductive units, and life-history changes. This opened new vistas for the developing brain, because it became possible to metabolically support transient patterns of brain organization as well as developmental brain plasticity for much longer period and with much greater number of neurons and connectivity combinations in comparison to apes. This included the shaping of cortical connections through the interaction with infant's social environment, which probably enhanced typically human evolution of language, cognition and self-awareness. In this review, we propose that the transient subplate zone and its postnatal remnant (interstitial neurons of the gyral white matter probably served as the main playground for evolution of these developmental shifts, and describe various features that makes human subplate uniquely positioned to have such a role in comparison with other primates.

  14. Experimental Study on Elastic-Plastic Behavior of SRC Columns with High Strength Steel

    OpenAIRE

    2006-01-01

    The demand to use high strength and high performance material because of large span and high rise of building in recent years. As to use of high-strength steel in composite steel and reinforced concrete structures, it remains to be clarified whether the ductile behavior can be ensured, especially when the high-strength steel is used in combination with High-strength concrete. This paper describes the test results on the elasto-plastic behavior of SRC column using high strength steel, and disc...

  15. A model of human motor sequence learning explains facilitation and interference effects based on spike-timing dependent plasticity.

    Science.gov (United States)

    Wang, Quan; Rothkopf, Constantin A; Triesch, Jochen

    2017-08-01

    The ability to learn sequential behaviors is a fundamental property of our brains. Yet a long stream of studies including recent experiments investigating motor sequence learning in adult human subjects have produced a number of puzzling and seemingly contradictory results. In particular, when subjects have to learn multiple action sequences, learning is sometimes impaired by proactive and retroactive interference effects. In other situations, however, learning is accelerated as reflected in facilitation and transfer effects. At present it is unclear what the underlying neural mechanism are that give rise to these diverse findings. Here we show that a recently developed recurrent neural network model readily reproduces this diverse set of findings. The self-organizing recurrent neural network (SORN) model is a network of recurrently connected threshold units that combines a simplified form of spike-timing dependent plasticity (STDP) with homeostatic plasticity mechanisms ensuring network stability, namely intrinsic plasticity (IP) and synaptic normalization (SN). When trained on sequence learning tasks modeled after recent experiments we find that it reproduces the full range of interference, facilitation, and transfer effects. We show how these effects are rooted in the network's changing internal representation of the different sequences across learning and how they depend on an interaction of training schedule and task similarity. Furthermore, since learning in the model is based on fundamental neuronal plasticity mechanisms, the model reveals how these plasticity mechanisms are ultimately responsible for the network's sequence learning abilities. In particular, we find that all three plasticity mechanisms are essential for the network to learn effective internal models of the different training sequences. This ability to form effective internal models is also the basis for the observed interference and facilitation effects. This suggests that STDP, IP, and SN

  16. Human Rights and Behavior Modification

    Science.gov (United States)

    Roos, Philip

    1974-01-01

    Criticisms of behavior modification, which charge that it violates ethical and legal principles, are discussed and reasons are presented to explain behavior modification's susceptibility to attack. (GW)

  17. Finite Element Modeling to Simulate the Elasto-Plastic Behavior of Polycrystalline in 718

    Science.gov (United States)

    Bonifaz, E. A.

    2013-01-01

    A 3D strain gradient plasticity finite element model was developed to simulate the elasto-plastic behavior of polycrystalline IN 718 alloys. The proposed model constructed in the basis of the so-called Kocks-Mecking model is used to determine the influence of microstructure attributes on the inelastic stress-strain distribution. Representative Volume Elements (RVEs) of different edge size but similar grain morphology and affordable computational meshes were tested to investigate the link between micro and macro variables of deformation and stress. The virtual specimens subjected to continuous monotonic straining loading conditions were constrained with random periodic boundary conditions. The difference in crystallographic orientation (which evolves in the process of straining) and the incompatibility of deformation between neighboring grains were accounted by the introduction of averaged Taylor factors and the evolution of geometrically necessary dislocation density. The effect of plastic deformation gradients imposed by the microstructure is clearly observed. Results demonstrate a strong dependence of flow stress and plastic strain on phase type and grain size. A main strategy for constitutive modeling of individual bulk grains is presented. The influence of the grain size on the aggregate response, in terms of local stress variations and aggregate elastic moduli was analyzed. It was observed that the elastic modulus in the bulk material is not dependent on grain size.

  18. Thermal behavior and kinetic study for catalytic co-pyrolysis of biomass with plastics.

    Science.gov (United States)

    Zhang, Xuesong; Lei, Hanwu; Zhu, Lei; Zhu, Xiaolu; Qian, Moriko; Yadavalli, Gayatri; Wu, Joan; Chen, Shulin

    2016-11-01

    The present study aims to investigate the thermal decomposition behaviors and kinetics of biomass (cellulose/Douglas fir sawdust) and plastics (LDPE) in a non-catalytic and catalytic co-pyrolysis over ZSM-5 catalyst by using a thermogravimetric analyzer (TGA). It was found that there was a positive synergistic interaction between biomass and plastics according to the difference of weight loss (ΔW), which could decrease the formation of solid residue at the end of the experiment. The first order reaction model well fitted for both non-catalytic and catalytic co-pyrolysis of biomass with plastics. The activation energy (E) of Cellulose-LDPE-Catalyst and DF-LDPE-Catalyst are only 89.51 and 54.51kJ/mol, respectively. The kinetics analysis showed that adding catalyst doesn't change the decomposition mechanism. As a result, the kinetic study on catalytic co-pyrolysis of biomass with plastics was suggested that the catalytic co-pyrolysis is a promising technique that can significantly reduce the energy input.

  19. Role of NMDA Receptors in Dopamine Neurons for Plasticity and Addictive Behaviors

    Science.gov (United States)

    Zweifel, Larry S.; Argilli, Emanuela; Bonci, Antonello; Palmiter, Richard D.

    2008-01-01

    Summary A single exposure to drugs of abuse produces an NMDA receptor (NMDAR)-dependent long-term potentiation (LTP) of AMPA receptor (AMPAR) currents in DA neurons; however, the importance of LTP for various aspects of drug addiction is unclear. To test the role of NMDAR-dependent plasticity in addictive behavior, we genetically inactivated functional NMDAR signaling exclusively in DA neurons (KO mice). Inactivation of NMDARs results in increased AMPAR-mediated transmission that is indistinguishable from the increases associated with a single cocaine exposure, yet locomotor responses to multiple drugs of abuse were unaltered in the KO mice. The initial phase of locomotor sensitization to cocaine is intact; however, the delayed sensitization that occurs with prolonged cocaine withdrawal did not occur. Conditioned behavioral responses for cocaine-testing environment were also absent in the KO mice. These findings provide evidence for a role of NMDAR signaling in DA neurons for specific behavioral modifications associated with drug seeking behaviors. PMID:18701073

  20. Human behavior representation of military teamwork

    OpenAIRE

    Martin, Michael W.

    2006-01-01

    This work presents a conceptual structure for the behaviors of artificial intelligence agents, with emphasis on creating teamwork through individual behaviors. The goal is to set up a framework which enables teams of simulation agents to behave more realistically. Better team behavior can lend a higher fidelity of human behavior representation in a simulation, as well as provide opportunities to experiment with the factors that create teamwork. The framework divides agent behaviors into three...

  1. Clinical science and human behavior.

    Science.gov (United States)

    Plaud, J J

    2001-09-01

    The debate between mentalism/cognitivism and behaviorism is analyzed, and it is concluded that behaviorism is the philosophy more closely associated with psychology as a behavioral science, the cognitive approach being more closely aligned with biological science. Specific objections to mentalistic interpretations of behavioral phenomena are detailed, and examples from clinical psychology are used to show the importance of behavioral approaches in applied domains. It is argued that the relation between behavior theory and clinical psychology is critical to the continued advancement of applied psychology. Behavior analysis is offered as a direct, applied extension of behavior theory as well as a highly practical and effective approach for understanding, explaining, and modifying the factors that contribute to and maintain maladaptive behaviors.

  2. The Cyclic Deformation Behavior of Severe Plastic Deformation (SPD Metals and the Influential Factors

    Directory of Open Access Journals (Sweden)

    Charles C. F. Kwan

    2012-02-01

    Full Text Available A deeper understanding of the mechanical behavior of ultra-fine (UF and nanocrystalline (NC grained metals is necessary with the growing interest in using UF and NC grained metals for structural applications. The cyclic deformation response and behavior of UF and NC grained metals is one aspect that has been gaining momentum as a major research topic for the past ten years. Severe Plastic Deformation (SPD materials are often in the spotlight for cyclic deformation studies as they are usually in the form of bulk work pieces and have UF and NC grains. Some well known techniques in the category of SPD processing are High Pressure Torsion (HPT, Equal Channel Angular Pressing (ECAP, and Accumulative Roll-Bonding (ARB. In this report, the literature on the cyclic deformation response and behavior of SPDed metals will be reviewed. The cyclic response of such materials is found to range from cyclic hardening to cyclic softening depending on various factors. Specifically, for SPDed UF grained metals, their behavior has often been associated with the observation of grain coarsening during cycling. Consequently, the many factors that affect the cyclic deformation response of SPDed metals can be summarized into three major aspects: (1 the microstructure stability; (2 the limitation of the cyclic lifespan; and lastly (3 the imposed plastic strain amplitude.

  3. Cocaine activates Rac1 to control structural and behavioral plasticity in caudate putamen.

    Science.gov (United States)

    Li, Juan; Zhang, Lei; Chen, Zhenzhong; Xie, Minjuan; Huang, Lu; Xue, Jinhua; Liu, Yutong; Liu, Nuyun; Guo, Fukun; Zheng, Yi; Kong, Jiming; Zhang, Lin; Zhang, Lu

    2015-03-01

    Repeated exposure to cocaine was previously found to cause sensitized behavioral responses and structural remodeling on medium spiny neurons of the nucleus accumbens (NAc) and caudate putamen (CPu). Rac1 has emerged as a key integrator of environmental cues that regulates dendritic cytoskeletons. In this study, we investigated the role of Rac1 in cocaine-induced dendritic and behavioral plasticity in the CPu. We found that Rac1 activation was reduced in the NAc but increased in the CPu following repeated cocaine treatment. Inhibition of Rac1 activity by a Rac1-specific inhibitor NSC23766, overexpression of a dominant negative mutant of Rac1 (T17N-Rac1) or local knockout of Rac1 attenuated the cocaine-induced increase in dendrites and spine density in the CPu, whereas overexpression of a constitutively active Rac1 exert the opposite effect. Moreover, NSC23766 reversed the increased number of asymmetric spine synapses in the CPu following chronic cocaine exposure. Downregulation of Rac1 activity likewise attenuates behavioral reward responses to cocaine exposure, with activation of Rac1 producing the opposite effect. Thus, Rac1 signaling is differentially regulated in the NAc and CPu after repeated cocaine treatment, and induction of Rac1 activation in the CPu is important for cocaine exposure-induced dendritic remodeling and behavioral plasticity.

  4. PLASTIC DEFORMATION BEHAVIOR OF ELECTROFORMED COPPER LINER OF SHAPED CHARGE AT DIFFERENT STRAIN RATES

    Institute of Scientific and Technical Information of China (English)

    H.Y. Gao; W.H. Tian; A.L. Fan; Q. Sun

    2003-01-01

    The paper deals with different plastic deformation behavior of electroformed copperliner of shaped charge, deformed at high strain rate (about 1×107 s-1) and normalstrain rate (4×10-4 s-1). The crystallographic orientation distribution of grains inrecovered slugs which had undergone high-strain-rate plastic deformation during ex-plosive detonation was investigated by electron backscattering Kikuchi pattern tech-nique. Cellular structures formed by tangled dislocations and sub-grain boundariesconsisting of dislocation arrays were detected in the recovered slugs. Some twins andslip dislocations were observed in specimen deformed at normal strain rate. It wasfound that dynamic recovery and recrystallization take place during high-strain-ratedeformation due to the temperature rising, whereas the conventional slip mechanismoperates during deformation at normal strain rate.

  5. PLASTIC DEFORMATION BEHAVIOR OF ELECTROFORMED COPPER LINER OF SHAPED CHARGE AT DIFFERENT STRAIN RATES

    Institute of Scientific and Technical Information of China (English)

    H.Y.Gao; Q.Sun

    2003-01-01

    The paper deals with different plastic deformation behavior of electroformed copper liner of shaped charge,depormed at high strain rate(about 1×107s-1) and normal strain rate (4×10-4s-1).The crystallographic orientation distribution of grains in recovered slugs which had undergone high-strain-rate plastic deformation during ex-plosive detonation was investigated by electron backscattering Kikuchi pattern tech-nique.Cellualar structures formed by tangled disocations and sub-grain boundaries consisting of dislocation arrays were detected in the recovered slugs.Some twins and slip dislocations were observed in specimen deformed at normal strain rate.It was found that dynamic recovery and recrystallization take place during high-strain-rate deformation due to the temperature rising,whereas the conventional slip mechanism operates during deformation at normal strain rate.

  6. Behavioral plasticity, behavioral syndromes and animal personality in crustacean decapods: An imperfect map is better than no map

    Institute of Scientific and Technical Information of China (English)

    Francesca GHERARDI; Laura AQUILONI; Elena TRICARICO

    2012-01-01

    Despite their key role as model organisms in many behavioral studies,crustacean decapods have been only slightly touched upon by the recent surge of scientific interest in animal personality.Only seven articles investigated the issue in a handful of species among hermit crabs,crabs,and crayfish.Obviously,a limited number of publications does not mean that personality is rare in decapods.On the contrary,few studies might be the result of a form of reluctance by behavioral ecologists to deal with such a phenomenon in these and other invertebrates.This reluctance contrasts with the enthusiasm shown in tackling the behavioral plasticity issue.Here we discuss the possible theoretical and methodological difficulties raised by applying the animal personality perspective to decapods and analyze implications of personality studies for their ecology,conservation,and welfare.By highlighting gaps in knowledge and directions of future research,our intention is to increase scientific emphasis on the issue.

  7. Mimesis: Linking Postmodern Theory to Human Behavior

    Science.gov (United States)

    Dybicz, Phillip

    2010-01-01

    This article elaborates mimesis as a theory of causality used to explain human behavior. Drawing parallels to social constructionism's critique of positivism and naturalism, mimesis is offered as a theory of causality explaining human behavior that contests the current dominance of Newton's theory of causality as cause and effect. The contestation…

  8. Ecological Environment in Terms of Human Behavior

    Institute of Scientific and Technical Information of China (English)

    Xiaogang; CHEN; Dehu; ZHOU; Hui; LIN

    2013-01-01

    In terms of human behavior,company and government policy,it is proposed that the ecological behavior of human being is the basis of influence on the ecological environment construction in Poyang Lake and measures to ensure the sustainable development of ecological environment in Poyang Lake.

  9. Human Behavior from a Chronobiological Perspective.

    Science.gov (United States)

    Hoskins, Carol Noll

    1980-01-01

    The rhythmic patterning of man's biochemical, physiological, and psychological behavior and the temporal relationships among various functions are the province of chronobiology. Citing animal and human studies, the author documents the progress of this new science and poses complex questions that it may answer about human behavior. (Editor/SJL)

  10. Rational Emotive Behavior Therapy: Humanism in Action.

    Science.gov (United States)

    Hill, Larry K.

    1996-01-01

    Claims that humanism, in both concept and philosophy, is encased in a literature that is predominantly abstract, making humanism difficult to translate into tangible day-to-day action. Argues that rational emotive behavior therapy (REBT), however, provides a detailed method for translating humanist concepts into humanist behavior. (RJM)

  11. Rational Emotive Behavior Therapy: Humanism in Action.

    Science.gov (United States)

    Hill, Larry K.

    1996-01-01

    Claims that humanism, in both concept and philosophy, is encased in a literature that is predominantly abstract, making humanism difficult to translate into tangible day-to-day action. Argues that rational emotive behavior therapy (REBT), however, provides a detailed method for translating humanist concepts into humanist behavior. (RJM)

  12. Low Doses of Ethanol Enhance LTD-like Plasticity in Human Motor Cortex.

    Science.gov (United States)

    Fuhl, Anna; Müller-Dahlhaus, Florian; Lücke, Caroline; Toennes, Stefan W; Ziemann, Ulf

    2015-12-01

    Humans liberally use ethanol for its facilitating effects on social interactions but its effects on central nervous system function remain underexplored. We have recently described that very low doses of ethanol abolish long-term potentiation (LTP)-like plasticity in human cortex, most likely through enhancement of tonic inhibition [Lücke et al, 2014, Neuropsychopharmacology 39:1508-18]. Here, we studied the effects of low-dose ethanol on long-term depression (LTD)-like plasticity. LTD-like plasticity was induced in human motor cortex by paired associative transcranial magnetic stimulation (PASLTD), and measured as decreases of motor evoked potential input-output curve (IO-curve). In addition, sedation was measured by decreases in saccade peak velocity (SPV). Ethanol in two low doses (EtOHethanol, easily reached during social drinking, enhance LTD-like plasticity in human cortex. This effect is most likely explained by the activation of extrasynaptic α4-subunit containing gamma-aminobutyric type A receptors by low-dose EtOH, resulting in increased tonic inhibition. Findings may stimulate cellular research on the role of tonic inhibition in regulating excitability and plasticity of cortical neuronal networks.

  13. Sleep recalibrates homeostatic and associative synaptic plasticity in the human cortex.

    Science.gov (United States)

    Kuhn, Marion; Wolf, Elias; Maier, Jonathan G; Mainberger, Florian; Feige, Bernd; Schmid, Hanna; Bürklin, Jan; Maywald, Sarah; Mall, Volker; Jung, Nikolai H; Reis, Janine; Spiegelhalder, Kai; Klöppel, Stefan; Sterr, Annette; Eckert, Anne; Riemann, Dieter; Normann, Claus; Nissen, Christoph

    2016-08-23

    Sleep is ubiquitous in animals and humans, but its function remains to be further determined. The synaptic homeostasis hypothesis of sleep-wake regulation proposes a homeostatic increase in net synaptic strength and cortical excitability along with decreased inducibility of associative synaptic long-term potentiation (LTP) due to saturation after sleep deprivation. Here we use electrophysiological, behavioural and molecular indices to non-invasively study net synaptic strength and LTP-like plasticity in humans after sleep and sleep deprivation. We demonstrate indices of increased net synaptic strength (TMS intensity to elicit a predefined amplitude of motor-evoked potential and EEG theta activity) and decreased LTP-like plasticity (paired associative stimulation induced change in motor-evoked potential and memory formation) after sleep deprivation. Changes in plasma BDNF are identified as a potential mechanism. Our study indicates that sleep recalibrates homeostatic and associative synaptic plasticity, believed to be the neural basis for adaptive behaviour, in humans.

  14. Sleep recalibrates homeostatic and associative synaptic plasticity in the human cortex

    Science.gov (United States)

    Kuhn, Marion; Wolf, Elias; Maier, Jonathan G.; Mainberger, Florian; Feige, Bernd; Schmid, Hanna; Bürklin, Jan; Maywald, Sarah; Mall, Volker; Jung, Nikolai H.; Reis, Janine; Spiegelhalder, Kai; Klöppel, Stefan; Sterr, Annette; Eckert, Anne; Riemann, Dieter; Normann, Claus; Nissen, Christoph

    2016-01-01

    Sleep is ubiquitous in animals and humans, but its function remains to be further determined. The synaptic homeostasis hypothesis of sleep–wake regulation proposes a homeostatic increase in net synaptic strength and cortical excitability along with decreased inducibility of associative synaptic long-term potentiation (LTP) due to saturation after sleep deprivation. Here we use electrophysiological, behavioural and molecular indices to non-invasively study net synaptic strength and LTP-like plasticity in humans after sleep and sleep deprivation. We demonstrate indices of increased net synaptic strength (TMS intensity to elicit a predefined amplitude of motor-evoked potential and EEG theta activity) and decreased LTP-like plasticity (paired associative stimulation induced change in motor-evoked potential and memory formation) after sleep deprivation. Changes in plasma BDNF are identified as a potential mechanism. Our study indicates that sleep recalibrates homeostatic and associative synaptic plasticity, believed to be the neural basis for adaptive behaviour, in humans. PMID:27551934

  15. Growth Kinetics, Characterization, and Plasticity of Human Menstrual Blood Stem Cells

    Directory of Open Access Journals (Sweden)

    Davood Mehrabani

    2016-03-01

    Full Text Available One of the readily available sources of mesenchymal stem cells (MSCs is menstrual blood-derived stem cells (Men-SCs, which exhibit characteristics similar to other types of MSCs. This study was performed to determine the growth kinetics, plasticity, and characterization of Men-SCs in women. During spring 2014 in the southern Iranian city of Shiraz, menstrual blood (5 mL was obtained from 10 women on their third day of menstruation in 2 age groups of 30 to 40 and 40 to 50 years old. Ficoll was used to separate the mononuclear cell fraction. After the Men-SCs were cultured, they were subcultured up to passage 4. Growth behavior and population doubling time were evaluated by seeding 5×104 cells into 12- and 24-well culture plates, and the colonies were enumerated. The expression of CD44, CD90, and CD34 was evaluated. The osteogenic potential was assessed by alizarin red staining. The Men-SCs were shown to be plastic adherent and spindle-shaped. Regarding the growth curves in the 12- and 24-well culture plates, it was demonstrated that in the women aged between 30 and 40 years, population doubling time was 55.5 and 62 hours, respectively, while these values in the women aged between 40 and 50 years were 70.4 and 72.4 hours, correspondingly. Positive expression of CD44 and CD90 and negative expression of CD34 were noted. In the osteogenic differentiation medium, the cells differentiated toward osteoblasts. As human Men-SCs are easily collectable without any invasive procedure and are a safe and rapid source of MSCs, they can be a good candidate for stem cell banking and cell transplantation in women.

  16. Somatic and Reinforcement-Based Plasticity in the Initial Stages of Human Motor Learning.

    Science.gov (United States)

    Sidarta, Ananda; Vahdat, Shahabeddin; Bernardi, Nicolò F; Ostry, David J

    2016-11-16

    As one learns to dance or play tennis, the desired somatosensory state is typically unknown. Trial and error is important as motor behavior is shaped by successful and unsuccessful movements. As an experimental model, we designed a task in which human participants make reaching movements to a hidden target and receive positive reinforcement when successful. We identified somatic and reinforcement-based sources of plasticity on the basis of changes in functional connectivity using resting-state fMRI before and after learning. The neuroimaging data revealed reinforcement-related changes in both motor and somatosensory brain areas in which a strengthening of connectivity was related to the amount of positive reinforcement during learning. Areas of prefrontal cortex were similarly altered in relation to reinforcement, with connectivity between sensorimotor areas of putamen and the reward-related ventromedial prefrontal cortex strengthened in relation to the amount of successful feedback received. In other analyses, we assessed connectivity related to changes in movement direction between trials, a type of variability that presumably reflects exploratory strategies during learning. We found that connectivity in a network linking motor and somatosensory cortices increased with trial-to-trial changes in direction. Connectivity varied as well with the change in movement direction following incorrect movements. Here the changes were observed in a somatic memory and decision making network involving ventrolateral prefrontal cortex and second somatosensory cortex. Our results point to the idea that the initial stages of motor learning are not wholly motor but rather involve plasticity in somatic and prefrontal networks related both to reward and exploration.

  17. Behavioral plasticity mediates asymmetric competition between invasive wasps and native ants.

    Science.gov (United States)

    Grangier, Julien; Lester, Philip J

    2012-03-01

    One of the most successful invasive species is the common wasp, Vespula vulgaris. We recently reported how foragers of this species have adopted previously unknown interference behavior when competing for food with native ants. Picking their opponents up in their mandibles, flying backward and dropping them some distance away from the disputed resource, wasps were shown to efficiently deal with a yet aggressive competitor and to modulate this behavior according to circumstances. Here we further discuss the nature and functioning of this unusual strategy. We first highlight the questions this interaction raises regarding the competitive advantages offered by asymmetries in body size and flight ability. Then, we argue that this study system illustrates the important role of behavioral plasticity in biological invasions; not only in the success of invaders but also in the ability of native species to coexist with these invaders.

  18. Augmenting LTP-Like Plasticity in Human Motor Cortex by Spaced Paired Associative Stimulation.

    Directory of Open Access Journals (Sweden)

    Florian Müller-Dahlhaus

    Full Text Available Paired associative stimulation (PASLTP of the human primary motor cortex (M1 can induce LTP-like plasticity by increasing corticospinal excitability beyond the stimulation period. Previous studies showed that two consecutive PASLTP protocols interact by homeostatic metaplasticity, but animal experiments provided evidence that LTP can be augmented by repeated stimulation protocols spaced by ~30 min. Here we tested in twelve healthy selected PASLTP responders the possibility that LTP-like plasticity can be augmented in the human M1 by systematically varying the interval between two consecutive PASLTP protocols. The first PASLTP protocol (PAS1 induced strong LTP-like plasticity lasting for 30-60 min. The effect of a second identical PASLTP protocol (PAS2 critically depended on the time between PAS1 and PAS2. At 10 min, PAS2 prolonged the PAS1-induced LTP-like plasticity. At 30 min, PAS2 augmented the LTP-like plasticity induced by PAS1, by increasing both magnitude and duration. At 60 min and 180 min, PAS2 had no effect on corticospinal excitability. The cumulative LTP-like plasticity after PAS1 and PAS2 at 30 min exceeded significantly the effect of PAS1 alone, and the cumulative PAS1 and PAS2 effects at 60 min and 180 min. In summary, consecutive PASLTP protocols interact in human M1 in a time-dependent manner. If spaced by 30 min, two consecutive PASLTP sessions can augment LTP-like plasticity in human M1. Findings may inspire further research on optimized therapeutic applications of non-invasive brain stimulation in neurological and psychiatric diseases.

  19. Augmenting LTP-Like Plasticity in Human Motor Cortex by Spaced Paired Associative Stimulation.

    Science.gov (United States)

    Müller-Dahlhaus, Florian; Lücke, Caroline; Lu, Ming-Kuei; Arai, Noritoshi; Fuhl, Anna; Herrmann, Eva; Ziemann, Ulf

    2015-01-01

    Paired associative stimulation (PASLTP) of the human primary motor cortex (M1) can induce LTP-like plasticity by increasing corticospinal excitability beyond the stimulation period. Previous studies showed that two consecutive PASLTP protocols interact by homeostatic metaplasticity, but animal experiments provided evidence that LTP can be augmented by repeated stimulation protocols spaced by ~30 min. Here we tested in twelve healthy selected PASLTP responders the possibility that LTP-like plasticity can be augmented in the human M1 by systematically varying the interval between two consecutive PASLTP protocols. The first PASLTP protocol (PAS1) induced strong LTP-like plasticity lasting for 30-60 min. The effect of a second identical PASLTP protocol (PAS2) critically depended on the time between PAS1 and PAS2. At 10 min, PAS2 prolonged the PAS1-induced LTP-like plasticity. At 30 min, PAS2 augmented the LTP-like plasticity induced by PAS1, by increasing both magnitude and duration. At 60 min and 180 min, PAS2 had no effect on corticospinal excitability. The cumulative LTP-like plasticity after PAS1 and PAS2 at 30 min exceeded significantly the effect of PAS1 alone, and the cumulative PAS1 and PAS2 effects at 60 min and 180 min. In summary, consecutive PASLTP protocols interact in human M1 in a time-dependent manner. If spaced by 30 min, two consecutive PASLTP sessions can augment LTP-like plasticity in human M1. Findings may inspire further research on optimized therapeutic applications of non-invasive brain stimulation in neurological and psychiatric diseases.

  20. Microbial hitchhikers on marine plastic debris: Human exposure risks at bathing waters and beach environments.

    Science.gov (United States)

    Keswani, Anisha; Oliver, David M; Gutierrez, Tony; Quilliam, Richard S

    2016-07-01

    Marine plastic debris is well characterized in terms of its ability to negatively impact terrestrial and marine environments, endanger coastal wildlife, and interfere with navigation, tourism and commercial fisheries. However, the impacts of potentially harmful microorganisms and pathogens colonising plastic litter are not well understood. The hard surface of plastics provides an ideal environment for opportunistic microbial colonisers to form biofilms and might offer a protective niche capable of supporting a diversity of different microorganisms, known as the "Plastisphere". This biotope could act as an important vector for the persistence and spread of pathogens, faecal indicator organisms (FIOs) and harmful algal bloom species (HABs) across beach and bathing environments. This review will focus on the existent knowledge and research gaps, and identify the possible consequences of plastic-associated microbes on human health, the spread of infectious diseases and bathing water quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. The relation between severe plastic deformation microstructure and corrosion behavior of AZ31 magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ben Hamu, G. [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Eliezer, D. [Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Institute of Materials Science and Engineering, TU Clausthal (Germany)], E-mail: deliezer@bgu.ac.il; Wagner, L. [Institute of Materials Science and Engineering, TU Clausthal (Germany)

    2009-01-22

    The quest for ever, higher performance in structural applications has resulted in the outgoing development of new or improved materials with novel crystallographic textures, microstructures, and compositions. However, commercial applicability of such materials depends heavily on the development of economical and robust manufacturing methods. Due to the promise of excellent properties, such as superplasticity, high strength, good ductility, enhanced high cycle fatigue life, and good corrosion resistance, interest has grown in nanostructure bulk materials. Those materials are defined most often as materials exhibiting nanocrystalline grain structures and particle sizes below 100 nm in at least one dimension. In recent years, bulk nanostructure materials processed by methods of severe plastic deformation (SPD) such as equal channel angular extrusion (ECAE) have attracted the growing interest of specialists in materials science. The main object of this research is to compare the microstructural changing and corrosion behavior of magnesium alloy AZ31 after extrusion and severe plastic deformation by ECAE process. The ECAE process can produce intense and uniform deformation by simple shear and provides a convenient procedure for introducing an ultra fine grain size into a material. The samples were prepared by using hot extrusion methods. Hardness and AC and DC polarization tests were carried out on the extruded rods, and the microstructure was examined using optical, electron microscopy (SEM, TEM) and EDS. The results showed that the severe plastic deformation process affected both the microstructure and the corrosion behavior of AZ31 Mg alloy. These results can be explained by the effects of the process on microstructure of AZ31 Mg alloy such as grain size and dislocation density caused by the change in recrystallization behavior.

  2. Short-Term Plasticity of a Thalamocortical Pathway Dynamically Modulated by Behavioral State

    Science.gov (United States)

    Castro-Alamancos, Manuel A.; Connors, Barry W.

    1996-04-01

    The neocortex receives information about the environment and the rest of the brain through pathways from the thalamus. These pathways have frequency-dependent properties that can strongly influence their effect on the neocortex. In 1943 Morison and Dempsey described "augmenting responses," a form of short-term plasticity in some thalamocortical pathways that is triggered by 8- to 15-hertz activation. Results from anesthetized rats showed that the augmenting response is initiated by pyramidal cells in layer V. The augmenting response was also observed in awake, unrestrained animals and was found to be dynamically modulated by their behavioral state.

  3. Composite Behavior of Lath Martensite Steels Induced by Plastic Strain, a New Paradigm for the Elastic-Plastic Response of Martensitic Steels

    Science.gov (United States)

    Ungár, Tamás; Harjo, Stefanus; Kawasaki, Takuro; Tomota, Yo; Ribárik, Gábor; Shi, Zengmin

    2017-01-01

    Based on high-resolution neutron diffraction experiments, we will show that in lath martensite steels, the initially homogeneous dislocation structure, i.e., homogeneous on the length scale of grain size, is disrupted by plastic deformation, which, in turn, produces a composite on the length scale of martensite lath packets. The diffraction patterns of plastically strained martensitic steel reveal characteristically asymmetric peak profiles in the same way as has been observed in materials with heterogeneous dislocation structures. The quasi homogeneous lath structure, formed by quenching, is disrupted by plastic deformation producing a composite structure. Lath packets oriented favorably or unfavorably for dislocation glide become soft or hard. Two lath packet types develop by work softening or work hardening in which the dislocation densities become smaller or larger compared to the initial average dislocation density. The decomposition into soft and hard lath packets is accompanied by load redistribution and the formation of long-range internal stresses between the two lath packet types. The composite behavior of plastically deformed lath martensite opens a new way to understand the elastic-plastic response in this class of materials.

  4. Insights into the Transcriptional Architecture of Behavioral Plasticity in the Honey Bee Apis mellifera

    KAUST Repository

    Khamis, Abdullah M.

    2015-06-15

    Honey bee colonies exhibit an age-related division of labor, with worker bees performing discrete sets of behaviors throughout their lifespan. These behavioral states are associated with distinct brain transcriptomic states, yet little is known about the regulatory mechanisms governing them. We used CAGEscan (a variant of the Cap Analysis of Gene Expression technique) for the first time to characterize the promoter regions of differentially expressed brain genes during two behavioral states (brood care (aka “nursing”) and foraging) and identified transcription factors (TFs) that may govern their expression. More than half of the differentially expressed TFs were associated with motifs enriched in the promoter regions of differentially expressed genes (DEGs), suggesting they are regulators of behavioral state. Strikingly, five TFs (nf-kb, egr, pax6, hairy, and clockwork orange) were predicted to co-regulate nearly half of the genes that were upregulated in foragers. Finally, differences in alternative TSS usage between nurses and foragers were detected upstream of 646 genes, whose functional analysis revealed enrichment for Gene Ontology terms associated with neural function and plasticity. This demonstrates for the first time that alternative TSSs are associated with stable differences in behavior, suggesting they may play a role in organizing behavioral state.

  5. Studying the mechanical behavior of a plastic, shock-resisting, antitank landmine.

    Science.gov (United States)

    Kirkpatrick Alberts, W C; Waxier, Roger; Sabatier, James M

    2006-12-01

    Modal behavior in landmines has recently become a topic of interest for acoustic landmine detection. It is well known that landmines exhibit mechanical resonance behavior that enhances the soil velocity over a buried landmine. Recent experimental work by Zagrai et al. [A. Zagrai, D. Donskoy, and A. Ekimov, J. Acoust. Soc. Am. 118 (6), 3619-3628 (2005)] demonstrates the existence of structural modes in several landmines. The work reported herein parallels the work of Zagrai et al. in studying the structural modes of the pressure plate of a plastic, cylindrically symmetric, antitank landmine. The pressure plate is considered to act as an elastically supported thin elastic plate. An observed perturbation of the first symmetric mode of the pressure plate is caused by the landmine's shock-resisting mechanism. This is validated by a lumped element model for the first symmetric mode coupled to the shock-resisting mechanism.

  6. A new bounding-surface plasticity model for cyclic behaviors of saturated clay

    Science.gov (United States)

    Hu, Cun; Liu, Haixiao

    2015-05-01

    A new combined isotropic-kinematic hardening rule is proposed based on the concept of the generalized homological center and the generalization of Masing's rule. The key point of the new hardening rule is that the unloading event can be treated as if it were virgin loading through taking the stress reversal point as the new generalized homological center of the bounding surface. Therefore, a new simple bounding-surface plasticity model with three important features for the cyclic behaviors of saturated clay is developed. Firstly, according to the movement of the generalized homological center, the model can harden not only isotropically but also kinematically to account for the anisotropy and memory the particular loading events. Secondly, the continuous cyclic loading is divided into the first loading, unloading and reloading processes and they are treated differently when calculating the hardening modulus to describe the soil responses accurately. The third feature is taking the generalized homological center as the mapping origin in the mapping rule to reflect the plastic flow in the unloading event. The behaviors of saturated clay for the monotonic and cyclic stress-controlled and strain-controlled triaxial tests are simulated by the model. The prediction results show an encouraging agreement with the experimental data.

  7. A Study of Hardening Behavior Based on a Finite-Deformation Gradient Crystal-Plasticity Model

    CERN Document Server

    Pouriayevali, Habib

    2016-01-01

    A systematic study on the different roles of the governing components of a well-defined finite-deformation gradient crystal-plasticity model proposed by (Gurtin, 2008b) is carried out, in order to visualize the capability of the model in the prediction of a wide range of hardening behaviors as well as rate-dependent, scale-variation and Bauschinger-like responses in a single crystal. A function of accumulation rates of dislocations is employed and viewed as a measure of formation of short-range interactions which impede dislocation movements within a crystal. The model is first represented in the reference configuration for the purpose of numerical implementation, and then implemented in the FEM software ABAQUS via a user-defined subroutine (UEL). Our simulation results reveal that the dissipative gradient-strengthening is also identified as a source of isotropic-hardening behavior, which represents the effect of cold work introduced by (Gurtin and Ohno, 2011). Moreover, plastic flows in predefined slip syste...

  8. Effect of serotonin on paired associative stimulation-induced plasticity in the human motor cortex.

    Science.gov (United States)

    Batsikadze, Giorgi; Paulus, Walter; Kuo, Min-Fang; Nitsche, Michael A

    2013-10-01

    Serotonin modulates diverse brain functions. Beyond its clinical antidepressant effects, it improves motor performance, learning and memory formation. These effects might at least be partially caused by the impact of serotonin on neuroplasticity, which is thought to be an important foundation of the respective functions. In principal accordance, selective serotonin reuptake inhibitors enhance long-term potentiation-like plasticity induced by transcranial direct current stimulation (tDCS) in humans. As other neuromodulators have discernable effects on different kinds of plasticity in humans, here we were interested to explore the impact of serotonin on paired associative stimulation (PAS)-induced plasticity, which induces a more focal kind of plasticity, as compared with tDCS, shares some features with spike timing-dependent plasticity, and is thought to be relative closely related to learning processes. In this single-blinded, placebo-controlled, randomized crossover study, we administered a single dose of 20 mg citalopram or placebo medication and applied facilitatory- and excitability-diminishing PAS to the left motor cortex of 14 healthy subjects. Cortico-spinal excitability was explored via single-pulse transcranial magnetic stimulation-elicited MEP amplitudes up to the next evening after plasticity induction. After citalopram administration, inhibitory PAS-induced after-effects were abolished and excitatory PAS-induced after-effects were enhanced trendwise, as compared with the respective placebo conditions. These results show that serotonin modulates PAS-induced neuroplasticity by shifting it into the direction of facilitation, which might help to explain mechanism of positive therapeutic effects of serotonin in learning and medical conditions characterized by enhanced inhibitory or reduced facilitatory plasticity, including depression and stroke.

  9. Sexual and seasonal plasticity in the emission of social electric signals. Behavioral approach and neural bases.

    Science.gov (United States)

    Silva, Ana; Quintana, Laura; Perrone, Rossana; Sierra, Felipe

    2008-01-01

    Behavior in electric fish includes modulations of a stereotyped electric organ discharge (EOD) in addition to locomotor displays. Gymnotiformes can modulate the EOD rate to produce signals that participate in different behaviors. We studied the reproductive behavior of Brachyhypopomus pinnicaudatus both in the wild and laboratory settings. During the breeding season, fish produce sexually dimorphic social electric signals (SES): males emit three types of chirps (distinguished by their duration and internal structure), and accelerations, whereas females interrupt their EOD. Since these SES imply EOD frequency modulations, the pacemaker nucleus (PN) is involved in their generation and constitutes the main target organ to explore seasonal and sexual plasticity of the CNS. The PN has two types of neurons, pacemakers and relays, which receive modulatory inputs from pre-pacemaker structures. These neurons show an anisotropic rostro-caudal and dorso-ventral distribution that is paralleled by different field potential waveforms in distinct portions of the PN. In vivo glutamate injections in different areas of the PN provoke different kinds of EOD rate modulations. Ventral injections produce chirp-like responses in breeding males and EOD interruptions in breeding females, whereas dorsal injections provoke EOD frequency rises in both sexes. In the non-breeding season, males and females respond with interruptions when stimulated ventrally and frequency rises when injected dorsally. Our results show that changes of glutamate effects in the PN could explain the seasonal and sexual differences in the generation of SES. By means of behavioral recordings both in the wild and in laboratory settings, and by electrophysiological and pharmacological experiments, we have identified sexual and seasonal plasticity of the CNS and explored its underlying mechanisms.

  10. Laboratory Investigation Of Partial Replacement Of Coarse Aggregate By Plastic Chips And Cement By Human Hair

    Directory of Open Access Journals (Sweden)

    A.S.Balaji

    2014-04-01

    Full Text Available The use of plastic is increasing day by day, although steps were taken to reduce its consumption. The suitability of recycled plastics as coarse aggregate in concrete and its advantage are discussed here. Experimental investigation was done using M20 mix and tests were carried out as per recommended procedures by relevant codes. As 100% replacement of natural coarse aggregate (NCA with plastic coarse aggregate (PCA is not feasible, partial replacement were examined. And also Hair is used as a fibred reinforcing material in concrete as partial replacement of cement. It has a high tensile strength which is equal to that of a copper wire with similar diameter. It is also available in abundance and at a very low cost. Tests were conducted to determine the properties of plastic aggregate and human hair such as density, specific gravity and crushing value. Experiments were conducted on concrete cubes with various percentages of human hair i.e. 0%, 0.5%, 1%, 1.5%, 2%, and 3% by weight of cement and with constant percentage of plastic aggregate as 20%.

  11. Influence of human behavior on cholera dynamics

    OpenAIRE

    Wang, Xueying; Gao, Daozhou; Wang, Jin

    2015-01-01

    This paper is devoted to studying the impact of human behavior on cholera infection. We start with a cholera ordinary differential equation (ODE) model that incorporates human behavior via modeling disease prevalence dependent contact rates for direct and indirect transmissions and infectious host shedding. Local and global dynamics of the model are analyzed with respect to the basic reproduction number. We then extend the ODE model to a reaction-convection-diffusion partial differential equa...

  12. S100B overexpression increases behavioral and neural plasticity in response to the social environment during adolescence.

    Science.gov (United States)

    Buschert, Jens; Hohoff, Christa; Touma, Chadi; Palme, Rupert; Rothermundt, Matthias; Arolt, Volker; Zhang, Weiqi; Ambrée, Oliver

    2013-11-01

    Genetic variants as well as increased serum levels of the neurotrophic factor S100B are associated with different psychiatric disorders. However, elevated S100B levels are also related to a better therapeutic outcome in psychiatric patients. The functional role of elevated S100B in psychiatric disorders is still unclear. Hence, this study was designed in order to elucidate the differential effects of S100B overexpression in interaction with chronic social stress during adolescence on emotional behavior and adult neurogenesis. S100B transgenic and wild-type mice were housed either in socially stable or unstable environments during adolescence, between postnatal days 28 and 77. In adulthood, anxiety-related behavior in the open field, dark-light, and novelty-induced suppression of feeding test as well as survival of proliferating hippocampal progenitor cells were assessed. S100B transgenic mice revealed significantly reduced anxiety-related behavior in the open field compared to wild-types when reared in stable social conditions. In contrast, when transgenic mice grew up in unstable social conditions, their level of anxiety-related behavior was comparable to the levels of wild-type mice. In addition, S100B overexpressing mice from unstable housing conditions displayed higher numbers of surviving newborn cells in the adult hippocampus which developed into mature neurons. In conclusion, elevated S100B levels increase the susceptibility to environmental stimuli during adolescence resulting in more variable behavioral and neural phenotypes in adulthood. In humans, this increased plasticity might lead to both, enhanced risk for psychiatric disorders in negative environments and improved therapeutic outcome in positive environments.

  13. Multiaxial mechanical properties and constitutive modeling of human adipose tissue: a basis for preoperative simulations in plastic and reconstructive surgery.

    Science.gov (United States)

    Sommer, Gerhard; Eder, Maximilian; Kovacs, Laszlo; Pathak, Heramb; Bonitz, Lars; Mueller, Christoph; Regitnig, Peter; Holzapfel, Gerhard A

    2013-11-01

    A preoperative simulation of soft tissue deformations during plastic and reconstructive surgery is desirable to support the surgeon's planning and to improve surgical outcomes. The current development of constitutive adipose tissue models, for the implementation in multilayer computational frameworks for the simulation of human soft tissue deformations, has proved difficult because knowledge of the required mechanical parameters of fat tissue is limited. Therefore, for the first time, human abdominal adipose tissues were mechanically investigated by biaxial tensile and triaxial shear tests. The results of this study suggest that human abdominal adipose tissues under quasi-static and dynamic multiaxial loadings can be characterized as a nonlinear, anisotropic and viscoelastic soft biological material. The nonlinear and anisotropic features are consequences of the material's collagenous microstructure. The aligned collagenous septa observed in histological investigations causes the anisotropy of the tissue. A hyperelastic model used in this study was appropriate to represent the quasi-static multiaxial mechanical behavior of fat tissue. The constitutive parameters are intended to serve as a basis for soft tissue simulations using the finite element method, which is an apparent method for obtaining promising results in the field of plastic and reconstructive surgery.

  14. GPA-14, a Gα(i) subunit mediates dopaminergic behavioral plasticity in C. elegans.

    Science.gov (United States)

    Mersha, Mahlet; Formisano, Rosaria; McDonald, Rochelle; Pandey, Pratima; Tavernarakis, Nektarios; Harbinder, Singh

    2013-04-22

    Precise levels of specific neurotransmitters are required for appropriate neuronal functioning. The neurotransmitter dopamine is implicated in modulating behaviors, such as cognition, reward and memory. In the nematode Caenorhabditis elegans, the release of dopamine during behavioral plasticity is in part modulated through an acid-sensing ion channel expressed in its eight dopaminergic neurons. A D2-like C. elegans dopamine receptor DOP-2 co-expresses along with a Gα(i) subunit (GPA-14) in the anterior deirid (ADE) pair of dopaminergic neurons. In follow-up experiments to our recently reported in vitro physical interaction between DOP-2 and GPA-14, we have behaviorally characterized worms carrying deletion mutations in gpa-14 and/or dop-2. We found both mutants to display behavioral abnormalities in habituation as well as associative learning, and exogenous supply of dopamine was able to revert the observed behavioral deficits. The behavioral phenotypes of dop-2 and gpa-14 loss-of-function mutants were found to be remarkably similar, and we did not observe any cumulative defects in their double mutants. Our results provide genetic and phenotypic support to our earlier in vitro results where we had shown that the DOP-2 dopamine receptor and the GPA-14 Gα(i) subunit physically interact with each other. Results from behavioral experiments presented here together with our previous in-vitro work suggests that the DOP-2 functions as a dopamine auto-receptor to modulate two types of learning, anterior touch habituation and chemosensory associative conditioning, through a G-protein complex that comprises GPA-14 as its Gα subunit.

  15. GPA-14, a Gαi subunit mediates dopaminergic behavioral plasticity in C. elegans

    Science.gov (United States)

    2013-01-01

    Background Precise levels of specific neurotransmitters are required for appropriate neuronal functioning. The neurotransmitter dopamine is implicated in modulating behaviors, such as cognition, reward and memory. In the nematode Caenorhabditis elegans, the release of dopamine during behavioral plasticity is in part modulated through an acid-sensing ion channel expressed in its eight dopaminergic neurons. A D2-like C. elegans dopamine receptor DOP-2 co-expresses along with a Gαi subunit (GPA-14) in the anterior deirid (ADE) pair of dopaminergic neurons. Findings In follow-up experiments to our recently reported in vitro physical interaction between DOP-2 and GPA-14, we have behaviorally characterized worms carrying deletion mutations in gpa-14 and/or dop-2. We found both mutants to display behavioral abnormalities in habituation as well as associative learning, and exogenous supply of dopamine was able to revert the observed behavioral deficits. The behavioral phenotypes of dop-2 and gpa-14 loss-of-function mutants were found to be remarkably similar, and we did not observe any cumulative defects in their double mutants. Conclusion Our results provide genetic and phenotypic support to our earlier in vitro results where we had shown that the DOP-2 dopamine receptor and the GPA-14 Gαi subunit physically interact with each other. Results from behavioral experiments presented here together with our previous in-vitro work suggests that the DOP-2 functions as a dopamine auto-receptor to modulate two types of learning, anterior touch habituation and chemosensory associative conditioning, through a G-protein complex that comprises GPA-14 as its Gα subunit. PMID:23607404

  16. Recognition of 48 Human Behaviors from Video

    NARCIS (Netherlands)

    Burghouts, G.J.; Bouma, H.; Hollander, R.J.M. den; Broek, S.P. van den; Schutte, K.

    2012-01-01

    We have developed a system that recognizes 48 human behaviors from video. The essential elements are (i) inference of the actors in the scene, (ii) assessment of event-related properties of actors and between actors, (iii) exploiting the event properties to recognize the behaviors. The performance o

  17. Synaptic plasticity in a recurrent neural network for versatile and adaptive behaviors of a walking robot

    Directory of Open Access Journals (Sweden)

    Eduard eGrinke

    2015-10-01

    Full Text Available Walking animals, like insects, with little neural computing can effectively perform complex behaviors. They can walk around their environment, escape from corners/deadlocks, and avoid or climb over obstacles. While performing all these behaviors, they can also adapt their movements to deal with an unknown situation. As a consequence, they successfully navigate through their complex environment. The versatile and adaptive abilities are the result of an integration of several ingredients embedded in their sensorimotor loop. Biological studies reveal that the ingredients include neural dynamics, plasticity, sensory feedback, and biomechanics. Generating such versatile and adaptive behaviors for a walking robot is a challenging task. In this study, we present a bio-inspired approach to solve this task. Specifically, the approach combines neural mechanisms with plasticity, sensory feedback, and biomechanics. The neural mechanisms consist of adaptive neural sensory processing and modular neural locomotion control. The sensory processing is based on a small recurrent network consisting of two fully connected neurons. Online correlation-based learning with synaptic scaling is applied to adequately change the connections of the network. By doing so, we can effectively exploit neural dynamics (i.e., hysteresis effects and single attractors in the network to generate different turning angles with short-term memory for a biomechanical walking robot. The turning information is transmitted as descending steering signals to the locomotion control which translates the signals into motor actions. As a result, the robot can walk around and adapt its turning angle for avoiding obstacles in different situations as well as escaping from sharp corners or deadlocks. Using backbone joint control embedded in the locomotion control allows the robot to climb over small obstacles. Consequently, it can successfully explore and navigate in complex environments.

  18. Scaling behavior of online human activity

    Science.gov (United States)

    Zhao, Zhi-Dan; Cai, Shi-Min; Huang, Junming; Fu, Yan; Zhou, Tao

    2012-11-01

    The rapid development of the Internet technology enables humans to explore the web and record the traces of online activities. From the analysis of these large-scale data sets (i.e., traces), we can get insights about the dynamic behavior of human activity. In this letter, the scaling behavior and complexity of human activity in the e-commerce, such as music, books, and movies rating, are comprehensively investigated by using the detrended fluctuation analysis technique and the multiscale entropy method. Firstly, the interevent time series of rating behaviors of these three types of media show similar scaling properties with exponents ranging from 0.53 to 0.58, which implies that the collective behaviors of rating media follow a process embodying self-similarity and long-range correlation. Meanwhile, by dividing the users into three groups based on their activities (i.e., rating per unit time), we find that the scaling exponents of the interevent time series in the three groups are different. Hence, these results suggest that a stronger long-range correlations exist in these collective behaviors. Furthermore, their information complexities vary in the three groups. To explain the differences of the collective behaviors restricted to the three groups, we study the dynamic behavior of human activity at the individual level, and find that the dynamic behaviors of a few users have extremely small scaling exponents associated with long-range anticorrelations. By comparing the interevent time distributions of four representative users, we can find that the bimodal distributions may bring forth the extraordinary scaling behaviors. These results of the analysis of the online human activity in the e-commerce may not only provide insight into its dynamic behaviors but may also be applied to acquire potential economic interest.

  19. Plasticity and stability of the visual system in human achiasma.

    Science.gov (United States)

    Hoffmann, Michael B; Kaule, Falko R; Levin, Netta; Masuda, Yoichiro; Kumar, Anil; Gottlob, Irene; Horiguchi, Hiroshi; Dougherty, Robert F; Stadler, Joerg; Wolynski, Barbara; Speck, Oliver; Kanowski, Martin; Liao, Yaping J; Wandell, Brian A; Dumoulin, Serge O

    2012-08-09

    The absence of the optic chiasm is an extraordinary and extreme abnormality in the nervous system. The abnormality produces highly atypical functional responses in the cortex, including overlapping hemifield representations and bilateral population receptive fields in both striate and extrastriate visual cortex. Even in the presence of these large functional abnormalities, the effect on visual perception and daily life is not easily detected. Here, we demonstrate that in two achiasmic humans the gross topography of the geniculostriate and occipital callosal connections remains largely unaltered. We conclude that visual function is preserved by reorganization of intracortical connections instead of large-scale reorganizations of the visual cortex. Thus, developmental mechanisms of local wiring within cortical maps compensate for the improper gross wiring to preserve function in human achiasma.

  20. Visual spatial attention has opposite effects on bidirectional plasticity in the human motor cortex.

    Science.gov (United States)

    Kamke, Marc R; Ryan, Alexander E; Sale, Martin V; Campbell, Megan E J; Riek, Stephan; Carroll, Timothy J; Mattingley, Jason B

    2014-01-22

    Long-term potentiation (LTP) and long-term depression (LTD) are key mechanisms of synaptic plasticity that are thought to act in concert to shape neural connections. Here we investigated the influence of visual spatial attention on LTP-like and LTD-like plasticity in the human motor cortex. Plasticity was induced using paired associative stimulation (PAS), which involves repeated pairing of peripheral nerve stimulation and transcranial magnetic stimulation to alter functional responses in the thumb area of the primary motor cortex. PAS-induced changes in cortical excitability were assessed using motor-evoked potentials. During plasticity induction, participants directed their attention to one of two visual stimulus streams located adjacent to each hand. When participants attended to visual stimuli located near the left thumb, which was targeted by PAS, LTP-like increases in excitability were significantly enhanced, and LTD-like decreases in excitability reduced, relative to when they attended instead to stimuli located near the right thumb. These differential effects on (bidirectional) LTP-like and LTD-like plasticity suggest that voluntary visual attention can exert an important influence on the functional organization of the motor cortex. Specifically, attention acts to both enhance the strengthening and suppress the weakening of neural connections representing events that fall within the focus of attention.

  1. Stimulus uncertainty enhances long-term potentiation-like plasticity in human motor cortex.

    Science.gov (United States)

    Sale, Martin V; Nydam, Abbey S; Mattingley, Jason B

    2017-03-01

    Plasticity can be induced in human cortex using paired associative stimulation (PAS), which repeatedly and predictably pairs a peripheral electrical stimulus with transcranial magnetic stimulation (TMS) to the contralateral motor region. Many studies have reported small or inconsistent effects of PAS. Given that uncertain stimuli can promote learning, the predictable nature of the stimulation in conventional PAS paradigms might serve to attenuate plasticity induction. Here, we introduced stimulus uncertainty into the PAS paradigm to investigate if it can boost plasticity induction. Across two experimental sessions, participants (n = 28) received a modified PAS paradigm consisting of a random combination of 90 paired stimuli and 90 unpaired (TMS-only) stimuli. Prior to each of these stimuli, participants also received an auditory cue which either reliably predicted whether the upcoming stimulus was paired or unpaired (no uncertainty condition) or did not predict the upcoming stimulus (maximum uncertainty condition). Motor evoked potentials (MEPs) evoked from abductor pollicis brevis (APB) muscle quantified cortical excitability before and after PAS. MEP amplitude increased significantly 15 min following PAS in the maximum uncertainty condition. There was no reliable change in MEP amplitude in the no uncertainty condition, nor between post-PAS MEP amplitudes across the two conditions. These results suggest that stimulus uncertainty may provide a novel means to enhance plasticity induction with the PAS paradigm in human motor cortex. To provide further support to the notion that stimulus uncertainty and prediction error promote plasticity, future studies should further explore the time course of these changes, and investigate what aspects of stimulus uncertainty are critical in boosting plasticity.

  2. Material characterization and finite element modelling of cyclic plasticity behavior for 304 stainless steel using a crystal plasticity model

    OpenAIRE

    Lu, Jiawa; Sun, Wei; Becker, Adib A.

    2016-01-01

    Low cycle fatigue tests were carried out for a 304 stainless steel at room temperature. A series of experimental characterisations, including SEM, TEM, and XRD were conducted for the 304 stainless steel to facilitate the understanding of the mechanical responses and microstructural behaviour of the material under cyclic loading including nanostructure, crystal structure and the fractured surface. The crystal plasticity finite element method (CPFEM) is a powerful tool for studying the microstr...

  3. Viscoelastic behavior of discrete human collagen fibrils

    DEFF Research Database (Denmark)

    Svensson, René; Hassenkam, Tue; Hansen, Philip

    2010-01-01

    Whole tendon and fibril bundles display viscoelastic behavior, but to the best of our knowledge this property has not been directly measured in single human tendon fibrils. In the present work an atomic force microscopy (AFM) approach was used for tensile testing of two human patellar tendon fibr...

  4. Simulating human behavior for national security human interactions.

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, Michael Lewis; Hart, Dereck H.; Verzi, Stephen J.; Glickman, Matthew R.; Wolfenbarger, Paul R.; Xavier, Patrick Gordon

    2007-01-01

    This 3-year research and development effort focused on what we believe is a significant technical gap in existing modeling and simulation capabilities: the representation of plausible human cognition and behaviors within a dynamic, simulated environment. Specifically, the intent of the ''Simulating Human Behavior for National Security Human Interactions'' project was to demonstrate initial simulated human modeling capability that realistically represents intra- and inter-group interaction behaviors between simulated humans and human-controlled avatars as they respond to their environment. Significant process was made towards simulating human behaviors through the development of a framework that produces realistic characteristics and movement. The simulated humans were created from models designed to be psychologically plausible by being based on robust psychological research and theory. Progress was also made towards enhancing Sandia National Laboratories existing cognitive models to support culturally plausible behaviors that are important in representing group interactions. These models were implemented in the modular, interoperable, and commercially supported Umbra{reg_sign} simulation framework.

  5. Human chromosomes: Structure, behavior, and effects

    Energy Technology Data Exchange (ETDEWEB)

    Therman, E.; Susman, M.

    1993-12-31

    The book `Human Chromosomes: Structure, Behavior, and Effects` covers the most important topics regarding human chromosomes and current research in cytogenetics. Attention is given both to structure and function of autosomes and sex chromosomes, as well as definitions and causes of chromosomal aberrations. This often involves discussion about various aspects of the cell cycle (both mitosis and meiosis). Methods and techniques involved in researching and mapping human chromosomes are also discussed.

  6. Fractal Analysis on Human Behaviors Dynamics

    CERN Document Server

    Fan, Chao; Zha, Yi-Long

    2010-01-01

    The study of human dynamics has attracted much interest from many fields recently. In this paper, the fractal characteristic of human behaviors is investigated from the perspective of time series constructed with the amount of library loans. The Hurst exponents and length of non-periodic cycles calculated through Rescaled Range Analysis indicate that the time series of human behaviors is fractal with long-range correlation. Then the time series are converted to complex networks by visibility graph algorithm. The topological properties of the networks, such as scale-free property, small-world effect and hierarchical structure imply that close relationships exist between the amounts of repetitious actions performed by people during certain periods of time, especially for some important days. Finally, the networks obtained are verified to be not fractal and self-similar using box-counting method. Our work implies the intrinsic regularity shown in human collective repetitious behaviors.

  7. Influence of human behavior on cholera dynamics.

    Science.gov (United States)

    Wang, Xueying; Gao, Daozhou; Wang, Jin

    2015-09-01

    This paper is devoted to studying the impact of human behavior on cholera infection. We start with a cholera ordinary differential equation (ODE) model that incorporates human behavior via modeling disease prevalence dependent contact rates for direct and indirect transmissions and infectious host shedding. Local and global dynamics of the model are analyzed with respect to the basic reproduction number. We then extend the ODE model to a reaction-convection-diffusion partial differential equation (PDE) model that accounts for the movement of both human hosts and bacteria. Particularly, we investigate the cholera spreading speed by analyzing the traveling wave solutions of the PDE model, and disease threshold dynamics by numerically evaluating the basic reproduction number of the PDE model. Our results show that human behavior can reduce (a) the endemic and epidemic levels, (b) cholera spreading speeds and (c) the risk of infection (characterized by the basic reproduction number). Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Altering strength and plastic deformation behavior via alloying and laminated structure in nanocrystalline metals

    Energy Technology Data Exchange (ETDEWEB)

    Gu, C. [State Key Laboratory for Mechanical Behavior of Material, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, F., E-mail: wangfei@mail.xjtu.edu.cn [State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an Jiaotong University, Xi' an 710049 (China); Huang, P., E-mail: huangping@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Material, Xi' an Jiaotong University, Xi' an 710049 (China); Lu, T.J. [State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi' an Jiaotong University, Xi' an 710049 (China); MOE Key Laboratory for Multifunctional Materials and Structures, Xi' an Jiaotong University, Xi' an 710049 (China); Xu, K.W. [State Key Laboratory for Mechanical Behavior of Material, Xi' an Jiaotong University, Xi' an 710049 (China)

    2015-07-29

    Nanoindentation and electron microscope techniques have been performed on sputtering deposited monolayered nanocrystalline CuNb and multilayered CuNb/Cu thin films. Microstructural features, hardness and surface morphologies of residual indentation have been evaluated to identify the effects of alloying and laminated structure on strength and plastic deformation behavior of nanocrystalline metals. By altering the content of Nb in CuNb alloy and adding crystalline Cu layers into CuNb alloy, the volume fraction of amorphous phase in CuNb alloy and interface structures changed dramatically, resulting in various trends that are related to hardness, indentation induced pileup and shear banding deformation. Based on the experimental results, the dominant deformation mechanisms of the CuNb and CuNb/Cu thin films with various Nb contents were proposed and extended to be discussed.

  9. Effects of Diet on Brain Plasticity in Animal and Human Studies: Mind the Gap

    Directory of Open Access Journals (Sweden)

    Tytus Murphy

    2014-01-01

    Full Text Available Dietary interventions have emerged as effective environmental inducers of brain plasticity. Among these dietary interventions, we here highlight the impact of caloric restriction (CR: a consistent reduction of total daily food intake, intermittent fasting (IF, every-other-day feeding, and diet supplementation with polyphenols and polyunsaturated fatty acids (PUFAs on markers of brain plasticity in animal studies. Moreover, we also discuss epidemiological and intervention studies reporting the effects of CR, IF and dietary polyphenols and PUFAs on learning, memory, and mood. In particular, we evaluate the gap in mechanistic understanding between recent findings from animal studies and those human studies reporting that these dietary factors can benefit cognition, mood, and anxiety, aging, and Alzheimer’s disease—with focus on the enhancement of structural and functional plasticity markers in the hippocampus, such as increased expression of neurotrophic factors, synaptic function and adult neurogenesis. Lastly, we discuss some of the obstacles to harnessing the promising effects of diet on brain plasticity in animal studies into effective recommendations and interventions to promote healthy brain function in humans. Together, these data reinforce the important translational concept that diet, a modifiable lifestyle factor, holds the ability to modulate brain health and function.

  10. Effects of diet on brain plasticity in animal and human studies: mind the gap.

    Science.gov (United States)

    Murphy, Tytus; Dias, Gisele Pereira; Thuret, Sandrine

    2014-01-01

    Dietary interventions have emerged as effective environmental inducers of brain plasticity. Among these dietary interventions, we here highlight the impact of caloric restriction (CR: a consistent reduction of total daily food intake), intermittent fasting (IF, every-other-day feeding), and diet supplementation with polyphenols and polyunsaturated fatty acids (PUFAs) on markers of brain plasticity in animal studies. Moreover, we also discuss epidemiological and intervention studies reporting the effects of CR, IF and dietary polyphenols and PUFAs on learning, memory, and mood. In particular, we evaluate the gap in mechanistic understanding between recent findings from animal studies and those human studies reporting that these dietary factors can benefit cognition, mood, and anxiety, aging, and Alzheimer's disease-with focus on the enhancement of structural and functional plasticity markers in the hippocampus, such as increased expression of neurotrophic factors, synaptic function and adult neurogenesis. Lastly, we discuss some of the obstacles to harnessing the promising effects of diet on brain plasticity in animal studies into effective recommendations and interventions to promote healthy brain function in humans. Together, these data reinforce the important translational concept that diet, a modifiable lifestyle factor, holds the ability to modulate brain health and function.

  11. A coupled damage-plasticity model for the cyclic behavior of shear-loaded interfaces

    Science.gov (United States)

    Carrara, P.; De Lorenzis, L.

    2015-12-01

    The present work proposes a novel thermodynamically consistent model for the behavior of interfaces under shear (i.e. mode-II) cyclic loading conditions. The interface behavior is defined coupling damage and plasticity. The admissible states' domain is formulated restricting the tangential interface stress to non-negative values, which makes the model suitable e.g. for interfaces with thin adherends. Linear softening is assumed so as to reproduce, under monotonic conditions, a bilinear mode-II interface law. Two damage variables govern respectively the loss of strength and of stiffness of the interface. The proposed model needs the evaluation of only four independent parameters, i.e. three defining the monotonic mode-II interface law, and one ruling the fatigue behavior. This limited number of parameters and their clear physical meaning facilitate experimental calibration. Model predictions are compared with experimental results on fiber reinforced polymer sheets externally bonded to concrete involving different load histories, and an excellent agreement is obtained.

  12. Omega-3 fatty acid deficiency during brain maturation reduces neuronal and behavioral plasticity in adulthood.

    Directory of Open Access Journals (Sweden)

    Harsharan Singh Bhatia

    Full Text Available Omega-3-fatty acid DHA is a structural component of brain plasma membranes, thereby crucial for neuronal signaling; however, the brain is inefficient at synthesizing DHA. We have asked how levels of dietary n-3 fatty acids during brain growth would affect brain function and plasticity during adult life. Pregnant rats and their male offspring were fed an n-3 adequate diet or n-3 deficient diets for 15 weeks. Results showed that the n-3 deficiency increased parameters of anxiety-like behavior using open field and elevated plus maze tests in the male offspring. Behavioral changes were accompanied by a level reduction in the anxiolytic-related neuropeptide Y-1 receptor, and an increase in the anxiogenic-related glucocorticoid receptor in the cognitive related frontal cortex, hypothalamus and hippocampus. The n-3 deficiency reduced brain levels of docosahexaenoic acid (DHA and increased the ratio n-6/n-3 assessed by gas chromatography. The n-3 deficiency reduced the levels of BDNF and signaling through the BDNF receptor TrkB, in proportion to brain DHA levels, and reduced the activation of the BDNF-related signaling molecule CREB in selected brain regions. The n-3 deficiency also disrupted the insulin signaling pathways as evidenced by changes in insulin receptor (IR and insulin receptor substrate (IRS. DHA deficiency during brain maturation reduces plasticity and compromises brain function in adulthood. Adequate levels of dietary DHA seem crucial for building long-term neuronal resilience for optimal brain performance and aiding in the battle against neurological disorders.

  13. Nutrition, epigenetics, and developmental plasticity: implications for understanding human disease.

    Science.gov (United States)

    Burdge, Graham C; Lillycrop, Karen A

    2010-08-21

    There is considerable evidence for induction of differential risk of noncommunicable diseases in humans by variation in the quality of the early life environment. Studies in animal models show that induction and stability of induced changes in the phenotype of the offspring involve altered epigenetic regulation by DNA methylation and covalent modifications of histones. These findings indicate that such epigenetic changes are highly gene specific and function at the level of individual CpG dinucleotides. Interventions using supplementation with folic acid or methyl donors during pregnancy, or folic acid after weaning, alter the phenotype and epigenotype induced by maternal dietary constraint during gestation. This suggests a possible means for reducing risk of induced noncommunicable disease, although the design and conduct of such interventions may require caution. The purpose of this review is to discuss recent advances in understanding the mechanism that underlies the early life origins of disease and to place these studies in a broader life-course context.

  14. Human synaptic plasticity gene expression profile and dendritic spine density changes in HIV-infected human CNS cells: role in HIV-associated neurocognitive disorders (HAND.

    Directory of Open Access Journals (Sweden)

    Venkata Subba Rao Atluri

    Full Text Available HIV-associated neurocognitive disorders (HAND is characterized by development of cognitive, behavioral and motor abnormalities, and occur in approximately 50% of HIV infected individuals. Our current understanding of HAND emanates mainly from HIV-1 subtype B (clade B, which is prevalent in USA and Western countries. However very little information is available on neuropathogenesis of HIV-1 subtype C (clade C that exists in Sub-Saharan Africa and Asia. Therefore, studies to identify specific neuropathogenic mechanisms associated with HAND are worth pursuing to dissect the mechanisms underlying this modulation and to prevent HAND particularly in clade B infection. In this study, we have investigated 84 key human synaptic plasticity genes differential expression profile in clade B and clade C infected primary human astrocytes by using RT(2 Profile PCR Array human Synaptic Plasticity kit. Among these, 31 and 21 synaptic genes were significantly (≥3 fold down-regulated and 5 genes were significantly (≥3 fold up-regulated in clade B and clade C infected cells, respectively compared to the uninfected control astrocytes. In flow-cytometry analysis, down-regulation of postsynaptic density and dendrite spine morphology regulatory proteins (ARC, NMDAR1 and GRM1 was confirmed in both clade B and C infected primary human astrocytes and SK-N-MC neuroblastoma cells. Further, spine density and dendrite morphology changes by confocal microscopic analysis indicates significantly decreased spine density, loss of spines and decreased dendrite diameter, total dendrite and spine area in clade B infected SK-N-MC neuroblastoma cells compared to uninfected and clade C infected cells. We have also observed that, in clade B infected astrocytes, induction of apoptosis was significantly higher than in the clade C infected astrocytes. In conclusion, this study suggests that down-regulation of synaptic plasticity genes, decreased dendritic spine density and induction of

  15. Plasticity in Single Axon Glutamatergic Connection to GABAergic Interneurons Regulates Complex Events in the Human Neocortex.

    Science.gov (United States)

    Szegedi, Viktor; Paizs, Melinda; Csakvari, Eszter; Molnar, Gabor; Barzo, Pal; Tamas, Gabor; Lamsa, Karri

    2016-11-01

    In the human neocortex, single excitatory pyramidal cells can elicit very large glutamatergic EPSPs (VLEs) in inhibitory GABAergic interneurons capable of triggering their firing with short (3-5 ms) delay. Similar strong excitatory connections between two individual neurons have not been found in nonhuman cortices, suggesting that these synapses are specific to human interneurons. The VLEs are crucial for generating neocortical complex events, observed as single pyramidal cell spike-evoked discharge of cell assemblies in the frontal and temporal cortices. However, long-term plasticity of the VLE connections and how the plasticity modulates neocortical complex events has not been studied. Using triple and dual whole-cell recordings from synaptically connected human neocortical layers 2-3 neurons, we show that VLEs in fast-spiking GABAergic interneurons exhibit robust activity-induced long-term depression (LTD). The LTD by single pyramidal cell 40 Hz spike bursts is specific to connections with VLEs, requires group I metabotropic glutamate receptors, and has a presynaptic mechanism. The LTD of VLE connections alters suprathreshold activation of interneurons in the complex events suppressing the discharge of fast-spiking GABAergic cells. The VLEs triggering the complex events may contribute to cognitive processes in the human neocortex, and their long-term plasticity can alter the discharging cortical cell assemblies by learning.

  16. Motor Skill Acquisition Promotes Human Brain Myelin Plasticity

    Directory of Open Access Journals (Sweden)

    Bimal Lakhani

    2016-01-01

    Full Text Available Experience-dependent structural changes are widely evident in gray matter. Using diffusion weighted imaging (DWI, the neuroplastic effect of motor training on white matter in the brain has been demonstrated. However, in humans it is not known whether specific features of white matter relate to motor skill acquisition or if these structural changes are associated to functional network connectivity. Myelin can be objectively quantified in vivo and used to index specific experience-dependent change. In the current study, seventeen healthy young adults completed ten sessions of visuomotor skill training (10,000 total movements using the right arm. Multicomponent relaxation imaging was performed before and after training. Significant increases in myelin water fraction, a quantitative measure of myelin, were observed in task dependent brain regions (left intraparietal sulcus [IPS] and left parieto-occipital sulcus. In addition, the rate of motor skill acquisition and overall change in myelin water fraction in the left IPS were negatively related, suggesting that a slower rate of learning resulted in greater neuroplastic change. This study provides the first evidence for experience-dependent changes in myelin that are associated with changes in skilled movements in healthy young adults.

  17. Effects of antiepileptic drugs on associative LTP-like plasticity in human motor cortex.

    Science.gov (United States)

    Heidegger, Tonio; Krakow, Karsten; Ziemann, Ulf

    2010-10-01

    Antiepileptic drugs (AEDs) are used extensively in clinical practice but relatively little is known on their specific effects at the systems level of human cortex. Here we tested, using a double-blind randomized placebo-controlled crossover design in healthy subjects, the effects of a single therapeutic oral dose of seven AEDs with different modes of action (tiagabine, diazepam, gabapentin, lamotrigine, topiramate, levetiracetam and piracetam) on long-term potentiation (LTP)-like motor cortical plasticity induced by paired associative transcranial magnetic stimulation (PAS). PAS-induced LTP-like plasticity was assessed from the increase in motor evoked potential amplitude in a hand muscle contralateral to the stimulated motor cortex. Levetiracetam significantly reduced LTP-like plasticity when compared to the placebo condition. Tiagabine, diazepam, lamotrigine and piracetam resulted in nonsignificant trends towards reduction of LTP-like plasticity while gabapentin and topiramate had no effect. The particularly depressant effect of levetiracetam is probably explained by its unique mode of action through binding at the vesicle membrane protein SV2A. Enhancement of gamma-amino butyric acid-dependent cortical inhibition by tiagabine, diazepam and possibly levetiracetam, and blockage of voltage-gated sodium channels by lamotrigine, may also depress PAS-induced LTP-like plasticity but these mechanisms appear to be less relevant. Findings may inform about AED-related adverse effects on important LTP-dependent central nervous systems processes such as learning or memory formation. The particular depressant effect of levetiracetam on LTP-like plasticity may also relate to the unique properties of this drug to inhibit epileptogenesis, a potentially LTP-associated process.

  18. Behavioral plasticity, behavioral syndromes and animal personality in crustacean decapods: An imperfect map is better than no map

    Directory of Open Access Journals (Sweden)

    Francesca GHERARDI, Laura AQUILONI, Elena TRICARICO

    2012-08-01

    Full Text Available Despite their key role as model organisms in many behavioral studies, crustacean decapods have been only slightly touched upon by the recent surge of scientific interest in animal personality. Only seven articles investigated the issue in a handful of species among hermit crabs, crabs, and crayfish. Obviously, a limited number of publications does not mean that personality is rare in decapods. On the contrary, few studies might be the result of a form of reluctance by behavioral ecologists to deal with such a phenomenon in these and other invertebrates. This reluctance contrasts with the enthusiasm shown in tackling the beha­vioral plasticity issue. Here we discuss the possible theoretical and methodological difficulties raised by applying the animal personality perspective to decapods and analyze implications of personality studies for their ecology, conservation, and welfare. By highlighting gaps in knowledge and directions of future research, our intention is to increase scientific emphasis on the issue [Current Zoology 58 (4: 567–579, 2012].

  19. Harnessing Brain Plasticity through Behavioral Techniques to Produce New Treatments in Neurorehabilitation

    Science.gov (United States)

    Taub, Edward

    2004-01-01

    Basic behavioral neuroscience research with monkeys has given rise to an efficacious new approach to the rehabilitation of movement after stroke, cerebral palsy, traumatic brain injury, and other types of neurological injury in humans termed Constraint-Induced Movement therapy or CI therapy. For the upper extremity, the treatment involves…

  20. Behavioral Entropy in Human-Robot Interaction

    Science.gov (United States)

    2004-01-01

    Department 2 Erwin R. Boer Consulting Brigham Young University San Diego, CA, USA Provo, UT, USA ABSTRACT The ability to quickly and accurately measure...AND ADDRESS(ES) Brigham Young University,Computer Science Department,33361 Talmage Building,Provo,UT,84602 8. PERFORMING ORGANIZATION REPORT NUMBER...in- teraction. To paraphrase Wiener, people work to re- duce entropy so skilled behavior minimizes entropy. This manifests itself in human behavior

  1. Nicotine Modifies Corticostriatal Plasticity and Amphetamine Rewarding Behaviors in Mice123

    Science.gov (United States)

    Storey, Granville P.; Heimbigner, Lauren; Walwyn, Wendy M.; Bamford, Nigel S.

    2016-01-01

    Abstract Corticostriatal signaling participates in sensitized responses to drugs of abuse, where short-term increases in dopamine availability provoke persistent, yet reversible, changes in glutamate release. Prior studies in mice show that amphetamine withdrawal promotes a chronic presynaptic depression in glutamate release, whereas an amphetamine challenge reverses this depression by potentiating corticostriatal activity in direct pathway medium spiny neurons. This synaptic plasticity promotes corticostriatal activity and locomotor sensitization through upstream changes in the activity of tonically active cholinergic interneurons (ChIs). We used a model of operant drug-taking behaviors, in which mice self-administered amphetamine through an in-dwelling catheter. Mice acquired amphetamine self-administration under fixed and increasing schedules of reinforcement. Following a period of abstinence, we determined whether nicotinic acetylcholine receptors modified drug-seeking behavior and associated alterations in ChI firing and corticostriatal activity. Mice responding to conditioned reinforcement showed reduced ChI and corticostriatal activity ex vivo, which paradoxically increased following an amphetamine challenge. Nicotine, in a concentration that increases Ca2+ influx and desensitizes α4β2*-type nicotinic receptors, reduced amphetamine-seeking behaviors following abstinence and amphetamine-induced locomotor sensitization. Nicotine blocked the depression of ChI firing and corticostriatal activity and the potentiating response to an amphetamine challenge. Together, these results demonstrate that nicotine reduces reward-associated behaviors following repeated amphetamine and modifies the changes in ChIs firing and corticostriatal activity. By returning glutamatergic activity in amphetamine self-administering mice to a more stable and normalized state, nicotine limits the depression of striatal activity in withdrawal and the increase in activity following

  2. Nicotine Modifies Corticostriatal Plasticity and Amphetamine Rewarding Behaviors in Mice(1,2,3).

    Science.gov (United States)

    Storey, Granville P; Gonzalez-Fernandez, Gabriel; Bamford, Ian J; Hur, Matthew; McKinley, Jonathan W; Heimbigner, Lauren; Minasyan, Ani; Walwyn, Wendy M; Bamford, Nigel S

    2016-01-01

    Corticostriatal signaling participates in sensitized responses to drugs of abuse, where short-term increases in dopamine availability provoke persistent, yet reversible, changes in glutamate release. Prior studies in mice show that amphetamine withdrawal promotes a chronic presynaptic depression in glutamate release, whereas an amphetamine challenge reverses this depression by potentiating corticostriatal activity in direct pathway medium spiny neurons. This synaptic plasticity promotes corticostriatal activity and locomotor sensitization through upstream changes in the activity of tonically active cholinergic interneurons (ChIs). We used a model of operant drug-taking behaviors, in which mice self-administered amphetamine through an in-dwelling catheter. Mice acquired amphetamine self-administration under fixed and increasing schedules of reinforcement. Following a period of abstinence, we determined whether nicotinic acetylcholine receptors modified drug-seeking behavior and associated alterations in ChI firing and corticostriatal activity. Mice responding to conditioned reinforcement showed reduced ChI and corticostriatal activity ex vivo, which paradoxically increased following an amphetamine challenge. Nicotine, in a concentration that increases Ca(2+) influx and desensitizes α4β2*-type nicotinic receptors, reduced amphetamine-seeking behaviors following abstinence and amphetamine-induced locomotor sensitization. Nicotine blocked the depression of ChI firing and corticostriatal activity and the potentiating response to an amphetamine challenge. Together, these results demonstrate that nicotine reduces reward-associated behaviors following repeated amphetamine and modifies the changes in ChIs firing and corticostriatal activity. By returning glutamatergic activity in amphetamine self-administering mice to a more stable and normalized state, nicotine limits the depression of striatal activity in withdrawal and the increase in activity following abstinence and

  3. Reactive oxygen species mediate visceral pain-related amygdala plasticity and behaviors.

    Science.gov (United States)

    Ji, Guangchen; Li, Zhen; Neugebauer, Volker

    2015-05-01

    Accumulating evidence suggests an important contribution of reactive oxygen species (ROS) to pain and neuropsychiatric disorders, but their role in pain-related plasticity in the brain is largely unknown. Neuroplasticity in the central nucleus of the amygdala (CeA) correlates positively with pain behaviors in different models. Little is known, however, about mechanisms of visceral pain-related amygdala changes. The electrophysiological and behavioral studies reported here addressed the role of ROS in the CeA in a visceral pain model induced by intracolonic zymosan. Vocalizations to colorectal distension and anxiety-like behavior increased after intracolonic zymosan and were inhibited by intra-CeA application of a ROS scavenger (tempol, a superoxide dismutase mimetic). Tempol also induced a place preference in zymosan-treated rats but not in controls. Single-unit recordings of CeA neurons in anesthetized rats showed increases of background activity and responses to visceral stimuli after intracolonic zymosan. Intra-CeA application of tempol inhibited the increased activity but had no effect under normal conditions. Whole-cell patch-clamp recordings of CeA neurons in brain slices from zymosan-treated rats showed that tempol decreased neuronal excitability and excitatory synaptic transmission of presumed nociceptive inputs from the brainstem (parabrachial area) through a combination of presynaptic and postsynaptic actions. Tempol had no effect in brain slices from sham controls. The results suggest that ROS contribute to visceral pain-related hyperactivity of amygdala neurons and amygdala-dependent behaviors through a mechanism that involves increased excitatory transmission and excitability of CeA neurons.

  4. Synaptic plasticity in a recurrent neural network for versatile and adaptive behaviors of a walking robot.

    Science.gov (United States)

    Grinke, Eduard; Tetzlaff, Christian; Wörgötter, Florentin; Manoonpong, Poramate

    2015-01-01

    Walking animals, like insects, with little neural computing can effectively perform complex behaviors. For example, they can walk around their environment, escape from corners/deadlocks, and avoid or climb over obstacles. While performing all these behaviors, they can also adapt their movements to deal with an unknown situation. As a consequence, they successfully navigate through their complex environment. The versatile and adaptive abilities are the result of an integration of several ingredients embedded in their sensorimotor loop. Biological studies reveal that the ingredients include neural dynamics, plasticity, sensory feedback, and biomechanics. Generating such versatile and adaptive behaviors for a many degrees-of-freedom (DOFs) walking robot is a challenging task. Thus, in this study, we present a bio-inspired approach to solve this task. Specifically, the approach combines neural mechanisms with plasticity, exteroceptive sensory feedback, and biomechanics. The neural mechanisms consist of adaptive neural sensory processing and modular neural locomotion control. The sensory processing is based on a small recurrent neural network consisting of two fully connected neurons. Online correlation-based learning with synaptic scaling is applied to adequately change the connections of the network. By doing so, we can effectively exploit neural dynamics (i.e., hysteresis effects and single attractors) in the network to generate different turning angles with short-term memory for a walking robot. The turning information is transmitted as descending steering signals to the neural locomotion control which translates the signals into motor actions. As a result, the robot can walk around and adapt its turning angle for avoiding obstacles in different situations. The adaptation also enables the robot to effectively escape from sharp corners or deadlocks. Using backbone joint control embedded in the the locomotion control allows the robot to climb over small obstacles

  5. Stress and the Adolescent Brain: Plasticity of Reproductive Behaviors in Female

    Directory of Open Access Journals (Sweden)

    Farideh Zafari Zangeneh

    2009-03-01

    Full Text Available Early life events influence life-long patterns of emotionality and stress responsiveness and alter the rate of brain and body aging.  Much research attention has focused on the programming effects of the hypothalamus pituitary axis (HPA in early life and on understanding HPA function in response to stressors in adulthood. In comparison, there has been relatively little research on adolescence, a time of significant brain development particularly in the frontal lobe and a time which is of great importance for mental and physical health. The hippocampus, amygdala, and prefrontal cortex undergo stress-induced structural remodeling, which alters behavioral and physiological responses. During adolescence, HPA function is characterized by a prolonged activation in response to stressors compared to adulthood, which may render ongoing development of the brain vulnerable. Stress reactivity is markedly influenced by both the pubertal maturation and the experience of the individual. The frequency of the pulses is increased in chronic stress, since the neuroendocrine system is such a good candidate for mediators of many diseases linked to chronic stress. The activity of HPA axis  in life time of female,  sex maturity, pregnancy or lactation is a plasticity of the diurnal rhythm of pulse amplitude; chronic stress can change this program for   formation disorder in behavioral and physiological responses.

  6. Experimental investigation and numerical simulation of plastic flow behavior during forward-backward-radial extrusion process

    Directory of Open Access Journals (Sweden)

    A. Farhoumand

    2016-12-01

    Full Text Available Finite element method was employed to investigate the effect of process parameters of plastic deformation behavior in Forward-Backward-Radial Extrusion (FBRE process. The result of an axisymmetric model shows that the friction between die components and the sample has a substantial effect on the material flow behavior. Although strain heterogeneity index (SHI slightly decreases with an increase in friction, large portion of the sample experiences significant strain heterogeneity. Increasing the friction factor also localizes the strain heterogeneity effect in the backward section, and spread the effect in the forward section. Decreasing the friction in the FBRE process can reduce the amount of the strain heterogeneity in the product while decreases the required punch force substantially. Furthermore, an increase in gap thickness increases the deformation in the area close to the lower punch at the expense of the area in the vicinity of the upper punch. The numerical simulation has a good agreement with the experimental results which confirms the accuracy of the proposed finite element model.

  7. Enhancement of extinction learning attenuates ethanol-seeking behavior and alters plasticity in the prefrontal cortex.

    Science.gov (United States)

    Gass, Justin T; Trantham-Davidson, Heather; Kassab, Amanda S; Glen, William B; Olive, M Foster; Chandler, L Judson

    2014-05-28

    Addiction is a chronic relapsing disorder in which relapse is often initiated by exposure to drug-related cues. The present study examined the effects of mGluR5 activation on extinction of ethanol-cue-maintained responding, relapse-like behavior, and neuronal plasticity. Rats were trained to self-administer ethanol and then exposed to extinction training during which they were administered either vehicle or the mGluR5 positive allosteric modulator 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl) or CDPPB. CDPPB treatment reduced active lever responding during extinction, decreased the total number of extinction sessions required to meet criteria, and attenuated cue-induced reinstatement of ethanol seeking. CDPPB facilitation of extinction was blocked by the local infusion of the mGluR5 antagonist 3-((2-methyl-4-thiazolyl)ethynyl) pyridine into the infralimbic (IfL) cortex, but had no effect when infused into the prelimbic (PrL) cortex. Analysis of dendritic spines revealed alterations in structural plasticity, whereas electrophysiological recordings demonstrated differential alterations in glutamatergic neurotransmission in the PrL and IfL cortex. Extinction was associated with increased amplitude of evoked synaptic PrL and IfL NMDA currents but reduced amplitude of PrL AMPA currents. Treatment with CDPPB prevented the extinction-induced enhancement of NMDA currents in PrL without affecting NMDA currents in the IfL. Whereas CDPPB treatment did not alter the amplitude of PrL or IfL AMPA currents, it did promote the expression of IfL calcium-permeable GluR2-lacking receptors in both abstinence- and extinction-trained rats, but had no effect in ethanol-naive rats. These results confirm changes in the PrL and IfL cortex in glutamatergic neurotransmission during extinction learning and demonstrate that manipulation of mGluR5 facilitates extinction of ethanol cues in association with neuronal plasticity.

  8. Microstructure Evolution and Mechanical Behavior of a Hot-Rolled High-Manganese Dual-Phase Transformation-Induced Plasticity/Twinning-Induced Plasticity Steel

    Science.gov (United States)

    Fu, Liming; Shan, Mokun; Zhang, Daoda; Wang, Huanrong; Wang, Wei; Shan, Aidang

    2017-05-01

    The microstructures and deformation behavior were studied in a high-temperature annealed high-manganese dual-phase (28 vol pct δ-ferrite and 72 vol pct γ-austenite) transformation-induced plasticity/twinning-induced plasticity (TRIP/TWIP) steel. The results showed that the steel exhibits a special Lüders-like yielding phenomenon at room temperature (RT) and 348 K (75 °C), while it shows continuous yielding at 423 K, 573 K and 673 K (150 °C, 300 °C and 400 °C) deformation. A significant TRIP effect takes place during Lüders-like deformation at RT and 348 K (75 °C) temperatures. Semiquantitative analysis of the TRIP effect on the Lüders-like yield phenomenon proves that a softening effect of the strain energy consumption of strain-induced transformation is mainly responsible for this Lüders-like phenomenon. The TWIP mechanism dominates the 423 K (150 °C) deformation process, while the dislocation glide controls the plasticity at 573 K (300 °C) deformation. The delta-ferrite, as a hard phase in annealed dual-phase steel, greatly affects the mechanical stability of austenite due to the heterogeneous strain distribution between the two phases during deformation. A delta-ferrite-aided TRIP effect, i.e., martensite transformation induced by localized strain concentration of the hard delta-ferrite, is proposed to explain this kind of Lüders-like phenomenon. Moreover, the tensile curve at RT exhibits an upward curved behavior in the middle deformation stage, which is principally attributed to the deformation twinning of austenite retained after Lüders-like deformation. The combination of the TRIP effect during Lüders-like deformation and the subsequent TWIP effect greatly enhances the ductility in this annealed high-manganese dual-phase TRIP/TWIP steel.

  9. Microstructure Evolution and Mechanical Behavior of a Hot-Rolled High-Manganese Dual-Phase Transformation-Induced Plasticity/Twinning-Induced Plasticity Steel

    Science.gov (United States)

    Fu, Liming; Shan, Mokun; Zhang, Daoda; Wang, Huanrong; Wang, Wei; Shan, Aidang

    2017-02-01

    The microstructures and deformation behavior were studied in a high-temperature annealed high-manganese dual-phase (28 vol pct δ-ferrite and 72 vol pct γ-austenite) transformation-induced plasticity/twinning-induced plasticity (TRIP/TWIP) steel. The results showed that the steel exhibits a special Lüders-like yielding phenomenon at room temperature (RT) and 348 K (75 °C), while it shows continuous yielding at 423 K, 573 K and 673 K (150 °C, 300 °C and 400 °C) deformation. A significant TRIP effect takes place during Lüders-like deformation at RT and 348 K (75 °C) temperatures. Semiquantitative analysis of the TRIP effect on the Lüders-like yield phenomenon proves that a softening effect of the strain energy consumption of strain-induced transformation is mainly responsible for this Lüders-like phenomenon. The TWIP mechanism dominates the 423 K (150 °C) deformation process, while the dislocation glide controls the plasticity at 573 K (300 °C) deformation. The delta-ferrite, as a hard phase in annealed dual-phase steel, greatly affects the mechanical stability of austenite due to the heterogeneous strain distribution between the two phases during deformation. A delta-ferrite-aided TRIP effect, i.e., martensite transformation induced by localized strain concentration of the hard delta-ferrite, is proposed to explain this kind of Lüders-like phenomenon. Moreover, the tensile curve at RT exhibits an upward curved behavior in the middle deformation stage, which is principally attributed to the deformation twinning of austenite retained after Lüders-like deformation. The combination of the TRIP effect during Lüders-like deformation and the subsequent TWIP effect greatly enhances the ductility in this annealed high-manganese dual-phase TRIP/TWIP steel.

  10. Scaling behavior of online human activity

    CERN Document Server

    Zhao, Zhi-Dan; Huang, Junming; Fu, Yan; Zhou, Tao; 10.1209/0295-5075/100/48004

    2013-01-01

    The rapid development of Internet technology enables human explore the web and record the traces of online activities. From the analysis of these large-scale data sets (i.e. traces), we can get insights about dynamic behavior of human activity. In this letter, the scaling behavior and complexity of human activity in the e-commerce, such as music, book, and movie rating, are comprehensively investigated by using detrended fluctuation analysis technique and multiscale entropy method. Firstly, the interevent time series of rating behaviors of these three type medias show the similar scaling property with exponents ranging from 0.53 to 0.58, which implies that the collective behaviors of rating media follow a process embodying self-similarity and long-range correlation. Meanwhile, by dividing the users into three groups based their activities (i.e., rating per unit time), we find that the scaling exponents of interevent time series in three groups are different. Hence, these results suggest the stronger long-rang...

  11. TG-MS study of the thermo-oxidative behavior of plastic automobile shredder residues.

    Science.gov (United States)

    Guo, Qingjie; Zhang, Xuan; Li, Chao; Liu, Xinmin; Li, Jinhui

    2012-03-30

    Automobile shredder residues (ASR) are materials that are rejected in the metal recovery process for end-of-life vehicles (ELV). These residues are composed of such materials as plastics, foams, glasses, rubbers, textiles, remaining metals and soils. ASR disposal is a difficult task, due to increasingly restrictive re-use policies. The pyrolytic reuse of ASR is one important option for energy recovery. The gas release behavior of pyrolyzed ASR was measured using a TG-MS apparatus, and this thermo-oxidative process was observed under different N(2)/O(2) volume ratios. The final weight/initial residue weight ratio for pyrolyzed ASR decreased from 43.4% to 10.1% with increasing oxygen concentrations. The production rates of hydrogen, methane and carbon dioxide also varied with different N(2)/O(2) volume ratios. The maximum emission of hydrogen and methane occurred when the thermo-oxidative atmosphere was entirely N(2). Temperature had a positive impact on hydrogen production, and the methane emission ratio reached a peak at the second shoulder of the devolatilization stage during which stage organic polymers were emitted. A peculiar characteristic of ASR is its content of nitrogen. The effects of ASR nitrogen content on N(2)O and NO(X) emissions were investigated in detail. NH(3) was the dominant nitrogen species that was released during ASR pyrolysis. N(2)O is highly temperature-sensitive and decomposes to N(2) at temperatures greater than 900°C.

  12. Plastic deformation behavior of Fe–Co–B–Si–Nb–Cr bulk metallic glasses under nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.T.; Hong, S.H.; Lee, C.H. [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Park, J.M., E-mail: jinman_park@hotmail.com [Materials Research Center, Samsung Advanced Institute of Technology (SAIT), San 14-1, Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-712 (Korea, Republic of); Kim, T.W.; Lee, W.H. [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Yim, H.I. [Department of Physics, Sookmyung Women’s University, Hyochangwongil 52, Yongsan-ku, Seoul 140-742 (Korea, Republic of); Kim, K.B., E-mail: kbkim@sejong.ac.kr [HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 98 Gunja-dong, Gwangjin-gu, Seoul 143-747 (Korea, Republic of)

    2014-02-25

    Highlights: • Additional Cr modulation of atomic structure of Fe-Co-B-Si-Nb BMGs. • An amount of free volume characterized by a combination of nanoindentation and AFM. • Free volume determined by height measurement of AFM after nanoindentation. -- Abstract: In this work, we investigate the effect of Cr addition on thermal properties and indentation behavior of Fe{sub 52}Co{sub 20−x}B{sub 20}Si{sub 4}Nb{sub 4}Cr{sub x} alloys with x = 0, 1, 3 and 5 at.%, respectively. Among all studied alloys, the Fe{sub 52}Co{sub 17}B{sub 20}Si{sub 4}Nb{sub 4}Cr{sub 3} bulk metallic glass (BMG) exhibits the highest thermal stability with large supercooled liquid region of 40 K and the pronounced plastic deformation features which is serrated flow (pop-in event) and significant pile-up of materials around indents. This demonstrates that the appropriate addition of Cr in Fe-based BMG can induce the internal atomic structure modulation and promote the mechanical softening, which are discussed in terms of free volume concept.

  13. A strategy to modulate the electrophoretic behavior in plastic microchips using sodium polystyrene sulfonate.

    Science.gov (United States)

    Guo, Jinxiu; Chen, Yu; Zhao, Lizhi; Sun, Ping; Li, Hongli; Zhou, Lei; Wang, Xiayan; Pu, Qiaosheng

    2016-12-16

    Plastic microchips have been broadly used as disposable microfluidic devices, but the poorly defined surface properties limit their application. Herein, we proved that an anionic polymer could be used as the background electrolyte (BGE) to provide a strong and stable cathodic electroosmotic flow (EOF) and modulate the electrophoretic behavior for efficient separation in relative thicker microchannels (∼75μm id). A cathodic EOF of ∼3.3×10(-4)cm(2)V(-1)s(-1) was maintained using sodium polystyrene sulfonate (PSSNa) with a molecular weight of 5×10(5) as the BGE, which ensured fluorescein isothiocyanate labeled biogenic amines (BAs) appeared ahead of other components in the electropherograms obtained with microchips of cyclic olefin copolymer. Four selected BAs appeared within 50s and theoretical plate numbers of 8.0×10(5)/m were achieved. The role of PSSNa was evaluated with streaming potential, dynamic light scattering, contact angle and atomic force microscopy. Its functionalities as surface modifier, viscosity regulator and pseudostationary phase were also confirmed. The proposed electrophoretic method was applied in the fast determination of BAs in fish meat samples.

  14. Odor experiences during preimaginal stages cause behavioral and neural plasticity in adult honeybees

    Directory of Open Access Journals (Sweden)

    Gabriela eRamirez

    2016-06-01

    Full Text Available In eusocial insects, experiences acquired during the development have long-term consequences on mature behavior. In the honeybee that suffers profound changes associated with metamorphosis, the effect of odor experiences at larval instars on the subsequent physiological and behavioral response is still unclear. To address the impact of preimaginal experiences on the adult honeybee, colonies containing larvae were fed scented food. The effect of the preimaginal experiences with the food odor was assessed in learning performance, memory retention and generalization in 3-5- and 17-19-day-old bees, in the regulation of their expression of synaptic-related genes and in theperception and morphology of their antennae. Three-5 day old bees that experienced 1-hexanol (1-HEX as food scent responded more to the presentation of the odor during the 1-HEX conditioning than control bees (i.e. bees reared in colonies fed unscented food. Higher levels of PER to 1-HEX in this group also extent to HEXA, the most perceptually similar odor to the experienced one that we tested. These results were not observed for the group tested at older ages. In the brain of young adults, larval experiences triggered similar levels of neurexins and neuroligins expression, two proteins that have been involved in synaptic formation after associative learning. At the sensory periphery, the experience did not alter the number of the olfactory sensilla placoidea, but did reduce the electrical response of the antennae to the experienced and novel odor. Our study provides a new insight into the effects of preimaginal experiences in the honeybee and the mechanisms underlying olfactory plasticity at larval stage of holometabolous insects.

  15. Odor Experiences during Preimaginal Stages Cause Behavioral and Neural Plasticity in Adult Honeybees

    Science.gov (United States)

    Ramírez, Gabriela; Fagundez, Carol; Grosso, Juan P.; Argibay, Pablo; Arenas, Andrés; Farina, Walter M.

    2016-01-01

    In eusocial insects, experiences acquired during the development have long-term consequences on mature behavior. In the honeybee that suffers profound changes associated with metamorphosis, the effect of odor experiences at larval instars on the subsequent physiological and behavioral response is still unclear. To address the impact of preimaginal experiences on the adult honeybee, colonies containing larvae were fed scented food. The effect of the preimaginal experiences with the food odor was assessed in learning performance, memory retention and generalization in 3–5- and 17–19 day-old bees, in the regulation of their expression of synaptic-related genes and in the perception and morphology of their antennae. Three-five day old bees that experienced 1-hexanol (1-HEX) as food scent responded more to the presentation of the odor during the 1-HEX conditioning than control bees (i.e., bees reared in colonies fed unscented food). Higher levels of proboscis extension response (PER) to 1-HEX in this group also extended to HEXA, the most perceptually similar odor to the experienced one that we tested. These results were not observed for the group tested at older ages. In the brain of young adults, larval experiences triggered similar levels of neurexins (NRXs) and neuroligins (Nlgs) expression, two proteins that have been involved in synaptic formation after associative learning. At the sensory periphery, the experience did not alter the number of the olfactory sensilla placoidea, but did reduce the electrical response of the antennae to the experienced and novel odor. Our study provides a new insight into the effects of preimaginal experiences in the honeybee and the mechanisms underlying olfactory plasticity at larval stage of holometabolous insects. PMID:27375445

  16. Megascale processes: Natural disasters and human behavior

    Science.gov (United States)

    Kieffer, S.W.; Barton, P.; Chesworth, W.; Palmer, A.R.; Reitan, P.; Zen, E.-A.

    2009-01-01

    Megascale geologic processes, such as earthquakes, tsunamis, volcanic eruptions, floods, and meteoritic impacts have occurred intermittently throughout geologic time, and perhaps on several planets. Unlike other catastrophes discussed in this volume, a unique process is unfolding on Earth, one in which humans may be the driving agent of megadisasters. Although local effects on population clusters may have been catastrophic in the past, human societies have never been interconnected globally at the scale that currently exists. We review some megascale processes and their effects in the past, and compare present conditions and possible outcomes. We then propose that human behavior itself is having effects on the planet that are comparable to, or greater than, these natural disasters. Yet, unlike geologic processes, human behavior is potentially under our control. Because the effects of our behavior threaten the stability, or perhaps even existence, of a civilized society, we call for the creation of a body to institute coherent global, credible, scientifi cally based action that is sensitive to political, economic, religious, and cultural values. The goal would be to institute aggressive monitoring, identify and understand trends, predict their consequences, and suggest and evaluate alternative actions to attempt to rescue ourselves and our ecosystems from catastrophe. We provide a template modeled after several existing national and international bodies. ?? 2009 The Geological Society of America.

  17. Human Behavior Cognition Using Smartphone Sensors

    Directory of Open Access Journals (Sweden)

    Jyrki Kaistinen

    2013-01-01

    Full Text Available This research focuses on sensing context, modeling human behavior and developing a new architecture for a cognitive phone platform. We combine the latest positioning technologies and phone sensors to capture human movements in natural environments and use the movements to study human behavior. Contexts in this research are abstracted as a Context Pyramid which includes six levels: Raw Sensor Data, Physical Parameter, Features/Patterns, Simple Contextual Descriptors, Activity-Level Descriptors, and Rich Context. To achieve implementation of the Context Pyramid on a cognitive phone, three key technologies are utilized: ubiquitous positioning, motion recognition, and human behavior modeling. Preliminary tests indicate that we have successfully achieved the Activity-Level Descriptors level with our LoMoCo (Location-Motion-Context model. Location accuracy of the proposed solution is up to 1.9 meters in corridor environments and 3.5 meters in open spaces. Test results also indicate that the motion states are recognized with an accuracy rate up to 92.9% using a Least Square-Support Vector Machine (LS-SVM classifier.

  18. Behavior genetic modeling of human fertility

    DEFF Research Database (Denmark)

    Rodgers, J L; Kohler, H P; Kyvik, K O

    2001-01-01

    Try) and number of children (NumCh). Behavior genetic models were fitted using structural equation modeling and DF analysis. A consistent medium-level additive genetic influence was found for NumCh, equal across genders; a stronger genetic influence was identified for FirstTry, greater for females than for males......Behavior genetic designs and analysis can be used to address issues of central importance to demography. We use this methodology to document genetic influence on human fertility. Our data come from Danish twin pairs born from 1953 to 1959, measured on age at first attempt to get pregnant (First...

  19. Presynaptic plasticity and memory : a behavioral analysis of short and long-term plasticity at the nerve terminal

    NARCIS (Netherlands)

    Hensbroek, Robert Alexander

    2001-01-01

    The ability to learn and remember enables animals and humans to adapt to their environment, avoid dangerous situations and adjust to social situations. Most neuroscientists agree that information storage in the brain is probably encoded by changes at the connections between neurons (the synapses).

  20. Presynaptic plasticity and memory : a behavioral analysis of short and long-term plasticity at the nerve terminal

    NARCIS (Netherlands)

    Hensbroek, Robert Alexander

    2001-01-01

    The ability to learn and remember enables animals and humans to adapt to their environment, avoid dangerous situations and adjust to social situations. Most neuroscientists agree that information storage in the brain is probably encoded by changes at the connections between neurons (the synapses). H

  1. Fate in humans of the plasticizer, DI (2-ethylhexyl) phthalate, arising from transfusion of platelets stored in vinyl plastic bags. [plasticizer migration into human blood from vinyl plastic bags during transfusion

    Science.gov (United States)

    Rubin, R. J.; Schiffer, C. A.

    1975-01-01

    Platelet concentrates were shown to contain 18-38 mg/100 ml of a phthalate plasticizer (DEHP) which arose by migration from the vinyl plastic packs in which the plateletes were prepared and stored. Transfusion of these platelets into 6 adult patients with leukemia resulted in peak blood plasma levels of DEHP ranging from 0.34 - 0.83 mg/100 ml. The blood levels fell mono-exponentially with a mean rate of 2.83 percent per minute and a half-life of 28.0 minutes. Urine was assayed by a method that would measure unchanged DEHP as well as all phthalic acid-containing metabolities. In two patients, at most 60 and 90% of the infused dose, respectively, was excreted in the urine collected for 24 hours post-transfusion. These estimates, however, could be high due to the simultaneous excretion of DEHP remaining from previous transfusions or arising from uncontrolled environmental exposures.

  2. Structuring policy problems for plastics, the environment and human health: reflections from the UK.

    Science.gov (United States)

    Shaxson, Louise

    2009-07-27

    How can we strengthen the science-policy interface for plastics, the environment and human health? In a complex policy area with multiple stakeholders, it is important to clarify the nature of the particular plastics-related issue before trying to understand how to reconcile the supply and demand for evidence in policy. This article proposes a simple problem typology to assess the fundamental characteristics of a policy issue and thus identify appropriate processes for science-policy interactions. This is illustrated with two case studies from one UK Government Department, showing how policy and science meet over the environmental problems of plastics waste in the marine environment and on land. A problem-structuring methodology helps us understand why some policy issues can be addressed through relatively linear flows of science from experts to policymakers but why others demand a more reflexive approach to brokering the knowledge between science and policy. Suggestions are given at the end of the article for practical actions that can be taken on both sides.

  3. Plasticity of the human visual system after retinal gene therapy in patients with Leber's congenital amaurosis.

    Science.gov (United States)

    Ashtari, Manzar; Zhang, Hui; Cook, Philip A; Cyckowski, Laura L; Shindler, Kenneth S; Marshall, Kathleen A; Aravand, Puya; Vossough, Arastoo; Gee, James C; Maguire, Albert M; Baker, Chris I; Bennett, Jean

    2015-07-15

    Much of our knowledge of the mechanisms underlying plasticity in the visual cortex in response to visual impairment, vision restoration, and environmental interactions comes from animal studies. We evaluated human brain plasticity in a group of patients with Leber's congenital amaurosis (LCA), who regained vision through gene therapy. Using non-invasive multimodal neuroimaging methods, we demonstrated that reversing blindness with gene therapy promoted long-term structural plasticity in the visual pathways emanating from the treated retina of LCA patients. The data revealed improvements and normalization along the visual fibers corresponding to the site of retinal injection of the gene therapy vector carrying the therapeutic gene in the treated eye compared to the visual pathway for the untreated eye of LCA patients. After gene therapy, the primary visual pathways (for example, geniculostriate fibers) in the treated retina were similar to those of sighted control subjects, whereas the primary visual pathways of the untreated retina continued to deteriorate. Our results suggest that visual experience, enhanced by gene therapy, may be responsible for the reorganization and maturation of synaptic connectivity in the visual pathways of the treated eye in LCA patients. The interactions between the eye and the brain enabled improved and sustained long-term visual function in patients with LCA after gene therapy.

  4. Low-grade inflammation disrupts structural plasticity in the human brain.

    Science.gov (United States)

    Szabó, C; Kelemen, O; Kéri, S

    2014-09-05

    Increased low-grade inflammation is thought to be associated with several neuropsychiatric disorders characterized by decreased neuronal plasticity. The purpose of the present study was to investigate the relationship between structural changes in the human brain during cognitive training and the intensity of low-grade peripheral inflammation in healthy individuals (n=56). A two-month training (30 min/day) with a platformer video game resulted in a significantly increased volume of the right hippocampal formation. The number of stressful life events experienced during the past year was associated with less pronounced enlargement of the hippocampus. However, the main predictor of hippocampal volume expansion was the relative peripheral expression of Nuclear Factor-κB (NF-κB), a transcription factor playing a central role in the effect of pro-inflammatory cytokines. Interleukin-6 (IL-6) and C-reactive protein levels were not related to hippocampal plasticity when NF-κB was taken into consideration. These results suggest that more intensive peripheral inflammation is associated with weaker neuronal plasticity during cognitive training. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  5. Alteration of Cingulate Long-Term Plasticity and Behavioral Sensitization to Inflammation by Environmental Enrichment

    Science.gov (United States)

    Shum, Fanny W. F.; Wu, Long-Jun; Zhao, Ming-Gao; Toyoda, Hiroki; Xu, Hui; Ren, Ming; Pinaud, Raphael; Ko, Shanelle W.; Lee, Yong-Seok; Kaang, Bong-Kiun; Zhuo, Min

    2007-01-01

    Exposure to an enriched environment (EE) has been shown to induce cortical plasticity. Considerable amount of research is focused on the effects of EE in the hippocampus; however, effects of EE on other brain regions and the mechanisms involved are not well known. To investigate this, we induced cortical plasticity by placing mice in an EE for one…

  6. Hearing it again and again: on-line subcortical plasticity in humans.

    Directory of Open Access Journals (Sweden)

    Erika Skoe

    Full Text Available BACKGROUND: Human brainstem activity is sensitive to local sound statistics, as reflected in an enhanced response in repetitive compared to pseudo-random stimulus conditions [1]. Here we probed the short-term time course of this enhancement using a paradigm that assessed how the local sound statistics (i.e., repetition within a five-note melody interact with more global statistics (i.e., repetition of the melody. METHODOLOGY/PRINCIPAL FINDINGS: To test the hypothesis that subcortical repetition enhancement builds over time, we recorded auditory brainstem responses in young adults to a five-note melody containing a repeated note, and monitored how the response changed over the course of 1.5 hrs. By comparing response amplitudes over time, we found a robust time-dependent enhancement to the locally repeating note that was superimposed on a weaker enhancement of the globally repeating pattern. CONCLUSIONS/SIGNIFICANCE: We provide the first demonstration of on-line subcortical plasticity in humans. This complements previous findings that experience-dependent subcortical plasticity can occur on a number of time scales, including life-long experiences with music and language, and short-term auditory training. Our results suggest that the incoming stimulus stream is constantly being monitored, even when the stimulus is physically invariant and attention is directed elsewhere, to augment the neural response to the most statistically salient features of the ongoing stimulus stream. These real-time transformations, which may subserve humans' strong disposition for grouping auditory objects, likely reflect a mix of local processes and corticofugal modulation arising from statistical regularities and the influences of expectation. Our results contribute to our understanding of the biological basis of statistical learning and initiate a new investigational approach relating to the time-course of subcortical plasticity. Although the reported time

  7. Reorganization and plastic changes of the human brain associated with skill learning and expertise

    Directory of Open Access Journals (Sweden)

    Yongmin eChang

    2014-02-01

    Full Text Available Novel experience and learning new skills are known as modulators of brain function. Advances in non-invasive brain imaging have provided new insight into structural and functional reorganization associated with skill learning and expertise. Especially, significant imaging evidences come from the domains of sports and music. Data from in vivo imaging studies in sports and music have provided vital information on plausible neural substrates contributing to brain reorganization underlying skill acquisition in humans. This mini review will attempt to take a narrow snapshot of imaging findings demonstrating functional and structural plasticity that mediate skill learning and expertise while identifying converging areas of interest and possible avenues for future research.

  8. Impact of global warming at the range margins: phenotypic plasticity and behavioral thermoregulation will buffer an endemic amphibian.

    Science.gov (United States)

    Ruiz-Aravena, Manuel; Gonzalez-Mendez, Avia; Estay, Sergio A; Gaitán-Espitia, Juan D; Barria-Oyarzo, Ismael; Bartheld, José L; Bacigalupe, Leonardo D

    2014-12-01

    When dispersal is not an option to evade warming temperatures, compensation through behavior, plasticity, or evolutionary adaptation is essential to prevent extinction. In this work, we evaluated whether there is physiological plasticity in the thermal performance curve (TPC) of maximum jumping speed in individuals acclimated to current and projected temperatures and whether there is an opportunity for behavioral thermoregulation in the desert landscape where inhabits the northernmost population of the endemic frog Pleurodema thaul. Our results indicate that individuals acclimated to 20°C and 25°C increased the breath of their TPCs by shifting their upper limits with respect to when they were acclimated at 10°C. In addition, even when dispersal is not possible for this population, the landscape is heterogeneous enough to offer opportunities for behavioral thermoregulation. In particular, under current climatic conditions, behavioral thermoregulation is not compulsory as available operative temperatures are encompassed within the population TPC limits. However, for severe projected temperatures under climate change, behavioral thermoregulation will be required in the sunny patches. In overall, our results suggest that this population of Pleurodema thaul will be able to endure the worst projected scenario of climate warming as it has not only the physiological capacities but also the environmental opportunities to regulate its body temperature behaviorally.

  9. Structure and mechanical behavior of human hair.

    Science.gov (United States)

    Yu, Yang; Yang, Wen; Wang, Bin; Meyers, Marc André

    2017-04-01

    The understanding of the mechanical behavior of hair under various conditions broadens our knowledge in biological materials science and contributes to the cosmetic industry. The hierarchical organization of hair is studied from the intermediate filament to the structural levels. The effects of strain rate, relative humidity, and temperature are evaluated. Hair exhibits a high tensile strength, 150-270MPa, which is significantly dependent on strain rate and humidity. The strain-rate sensitivity, approximately 0.06-0.1, is comparable to that of other keratinous materials and common synthetic polymers. The structures of the internal cortex and surface cuticle are affected by the large tensile extension. One distinguishing feature, the unwinding of the α-helix and the possible transformation to β-sheet structure of keratin under tension, which affects the ductility of hair, is analytically evaluated and incorporated into a constitutive equation. A good agreement with the experimental results is obtained. This model elucidates the tensile response of the α-keratin fibers. The contributions of elastic and plastic strains on reloading are evaluated and correlated to structural changes. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Metaplasticity and Behavior: How Training and Inflammation Affect Plastic Potential within the Spinal Cord and Recovery after Injury

    Directory of Open Access Journals (Sweden)

    James W Grau

    2014-09-01

    Full Text Available Research has shown that spinal circuits have the capacity to adapt in response to training, nociceptive stimulation and peripheral inflammation. These changes in neural function are mediated by physiological and neurochemical systems analogous to those that support plasticity within the hippocampus (e.g., long-term potentiation and the NMDA receptor. As observed in the hippocampus, engaging spinal circuits can have a lasting impact on plastic potential, enabling or inhibiting the capacity to learn. These effects are related to the concept of metaplasticity. Behavioral paradigms are described that induce metaplastic effects within the spinal cord. Uncontrollable/unpredictable stimulation, and peripheral inflammation, induce a form of maladaptive plasticity that inhibits spinal learning. Conversely, exposure to controllable or predictable stimulation engages a form of adaptive plasticity that counters these maladaptive effects and enables learning. Adaptive plasticity is tied to an up-regulation of brain derived neurotrophic factor (BDNF. Maladaptive plasticity is linked to processes that involve kappa opioids, the metabotropic glutamate (mGlu receptor, glia, and the cytokine tumor necrosis factor (TNF. Uncontrollable nociceptive stimulation also impairs recovery after a spinal contusion injury and fosters the development of pain (allodynia. These adverse effects are related to an up-regulation of TNF and a down-regulation of BDNF and its receptor (TrkB. In the absence of injury, brain systems quell the sensitization of spinal circuits through descending serotonergic fibers and the serotonin 1A (5HT 1A receptor. This protective effect is blocked by surgical anesthesia. Disconnected from the brain, intracellular Cl- concentrations increase (due to a down-regulation of the cotransporter KCC2, which causes GABA to have an excitatory effect. It is suggested that BDNF has a restorative effect because it up-regulates KCC2 and re-establishes GABA

  11. TrkB/BDNF-dependent striatal plasticity and behavior in a genetic model of epilepsy: modulation by valproic acid.

    Science.gov (United States)

    Ghiglieri, Veronica; Sgobio, Carmelo; Patassini, Stefano; Bagetta, Vincenza; Fejtova, Anna; Giampà, Carmela; Marinucci, Silvia; Heyden, Alexandra; Gundelfinger, Eckart D; Fusco, Francesca R; Calabresi, Paolo; Picconi, Barbara

    2010-06-01

    In mice lacking the central domain of the presynaptic scaffold Bassoon the occurrence of repeated cortical seizures induces cell-type-specific plasticity changes resulting in a general enhancement of the feedforward inhibition within the striatal microcircuit. Early antiepileptic treatment with valproic acid (VPA) reduces epileptic attacks, inhibits the emergence of pathological form of plasticity in fast-spiking (FS) interneurons and restores physiological striatal synaptic plasticity in medium spiny (MS) neurons. Brain-derived neurotrophic factor (BDNF) is a key factor for the induction and maintenance of synaptic plasticity and it is also implicated in the mechanisms underlying epilepsy-induced adaptive changes. In this study, we explore the possibility that the TrkB/BDNF system is involved in the striatal modifications associated with the Bassoon gene (Bsn) mutation. In epileptic mice abnormal striatum-dependent learning was paralleled by higher TrkB levels and an altered distribution of BDNF. Accordingly, subchronic intrastriatal administration of k252a, an inhibitor of TrkB receptor tyrosine kinase activity, reversed behavioral alterations in Bsn mutant mice. In addition, in vitro manipulations of the TrkB/BDNF complex by k252a, prevented the emergence of pathological plasticity in FS interneurons. Chronic treatment with VPA, by reducing seizures, was able to rebalance TrkB to control levels favoring a physiological redistribution of BDNF between MS neurons and FS interneurons with a concomitant recovery of striatal plasticity. Our results provide the first indication that BDNF is involved in determining the striatal alterations occurring in the early-onset epileptic syndrome associated with the absence of presynaptic protein Bassoon.

  12. Metaplasticity and behavior: how training and inflammation affect plastic potential within the spinal cord and recovery after injury

    Science.gov (United States)

    Grau, James W.; Huie, J. Russell; Lee, Kuan H.; Hoy, Kevin C.; Huang, Yung-Jen; Turtle, Joel D.; Strain, Misty M.; Baumbauer, Kyle M.; Miranda, Rajesh M.; Hook, Michelle A.; Ferguson, Adam R.; Garraway, Sandra M.

    2014-01-01

    Research has shown that spinal circuits have the capacity to adapt in response to training, nociceptive stimulation and peripheral inflammation. These changes in neural function are mediated by physiological and neurochemical systems analogous to those that support plasticity within the hippocampus (e.g., long-term potentiation and the NMDA receptor). As observed in the hippocampus, engaging spinal circuits can have a lasting impact on plastic potential, enabling or inhibiting the capacity to learn. These effects are related to the concept of metaplasticity. Behavioral paradigms are described that induce metaplastic effects within the spinal cord. Uncontrollable/unpredictable stimulation, and peripheral inflammation, induce a form of maladaptive plasticity that inhibits spinal learning. Conversely, exposure to controllable or predictable stimulation engages a form of adaptive plasticity that counters these maladaptive effects and enables learning. Adaptive plasticity is tied to an up-regulation of brain derived neurotrophic factor (BDNF). Maladaptive plasticity is linked to processes that involve kappa opioids, the metabotropic glutamate (mGlu) receptor, glia, and the cytokine tumor necrosis factor (TNF). Uncontrollable nociceptive stimulation also impairs recovery after a spinal contusion injury and fosters the development of pain (allodynia). These adverse effects are related to an up-regulation of TNF and a down-regulation of BDNF and its receptor (TrkB). In the absence of injury, brain systems quell the sensitization of spinal circuits through descending serotonergic fibers and the serotonin 1A (5HT 1A) receptor. This protective effect is blocked by surgical anesthesia. Disconnected from the brain, intracellular Cl- concentrations increase (due to a down-regulation of the cotransporter KCC2), which causes GABA to have an excitatory effect. It is suggested that BDNF has a restorative effect because it up-regulates KCC2 and re-establishes GABA-mediated inhibition

  13. Associative stimulation of the supraorbital nerve fails to induce timing-specific plasticity in the human blink reflex

    DEFF Research Database (Denmark)

    Zeuner, Kirsten E; Knutzen, Arne; Al-Ali, Asmaa;

    2010-01-01

    Associative high-frequency electrical stimulation (HFS) of the supraorbital nerve in five healthy individuals induced long-term potentiation (LTP)-like or depression (LTD)-like changes in the human blink reflex circuit according to the rules of spike timing-dependent plasticity (Mao and Evinger...... the orbicularis oculi muscles, HFS(LTP) induced excessive LTP-like associative plasticity relative to healthy controls, which was normalized after botulinum toxin (BTX) injections (Quartarone et al, 2006)....

  14. Adaptive behavior of neighboring neurons during adaptation-induced plasticity of orientation tuning in V1

    Directory of Open Access Journals (Sweden)

    Shumikhina Svetlana

    2009-12-01

    Full Text Available Abstract Background Sensory neurons display transient changes of their response properties following prolonged exposure to an appropriate stimulus (adaptation. In adult cat primary visual cortex, orientation-selective neurons shift their preferred orientation after being adapted to a non-preferred orientation. The direction of those shifts, towards (attractive or away (repulsive from the adapter depends mostly on adaptation duration. How the adaptive behavior of a neuron is related to that of its neighbors remains unclear. Results Here we show that in most cases (75%, cells shift their preferred orientation in the same direction as their neighbors. We also found that cells shifting preferred orientation differently from their neighbors (25% display three interesting properties: (i larger variance of absolute shift amplitude, (ii wider tuning bandwidth and (iii larger range of preferred orientations among the cluster of cells. Several response properties of V1 neurons depend on their location within the cortical orientation map. Our results suggest that recording sites with both attractive and repulsive shifts following adaptation may be located in close proximity to iso-orientation domain boundaries or pinwheel centers. Indeed, those regions have a more diverse orientation distribution of local inputs that could account for the three properties above. On the other hand, sites with all cells shifting their preferred orientation in the same direction could be located within iso-orientation domains. Conclusions Our results suggest that the direction and amplitude of orientation preference shifts in V1 depend on location within the orientation map. This anisotropy of adaptation-induced plasticity, comparable to that of the visual cortex itself, could have important implications for our understanding of visual adaptation at the psychophysical level.

  15. Microstructural evolution and deformation behavior of twinning-induced plasticity (TWIP) steel during wire drawing

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Joong-Ki [Graduate Institute of Ferrous Technology, POSTECH, Pohang 790-784 (Korea, Republic of); Steel Products Research Group, Technical Research Laboratories, POSCO, Pohang 790-785 (Korea, Republic of); Yi, Il-Cheol [Graduate Institute of Ferrous Technology, POSTECH, Pohang 790-784 (Korea, Republic of); Son, Il-Heon; Yoo, Jang-Yong [Steel Products Research Group, Technical Research Laboratories, POSCO, Pohang 790-785 (Korea, Republic of); Kim, Byoungkoo [Materials Technology Development Team, DHIC, Changwon 642-792 (Korea, Republic of); Zargaran, A. [Graduate Institute of Ferrous Technology, POSTECH, Pohang 790-784 (Korea, Republic of); Kim, Nack J., E-mail: njkim@postech.ac.kr [Graduate Institute of Ferrous Technology, POSTECH, Pohang 790-784 (Korea, Republic of)

    2015-09-17

    The effect of wire drawing on the microstructural evolution and deformation behavior of Fe–Mn–Al–C twinning-induced plasticity (TWIP) steel has been investigated. The inhomogeneities of the stress state, texture, microstructure, and mechanical properties were clarified over the cross section of drawn wire with the aid of numerical simulation, Schmid factor analysis, and electron backscatter diffraction (EBSD) techniques. The analysis of texture in drawn wire shows that a mixture of <111> and <100> fiber texture was developed with strain; however, the distribution of <111> and <100> fibers was inhomogeneous along the radial direction of wire due to uneven strain distribution and different stress state along the radial direction. It has also been shown that the morphology, volume fraction, and variant system of twins as well as twinning rate were dependent on the imposed stress state. The surface area was subjected to larger strain and more complex stress state involving compression, shear, and tension than the center area, resulting in a larger twin volume fraction and more twin variants in the former than in the latter at all the strain levels. While the surface area was saturated with twins at an early stage of drawing, the center area was not saturated with twins even at fracture, implying that the fracture of wire were initiated at the surface area because of the exhaustion of ductility due to twinning. Based on these results, it is suggested that imposing a uniform strain distribution along the radial direction of wire by the control of processing conditions such as die angle and amount of reduction per pass is necessary to increase the drawing limit of TWIP steel.

  16. Human behavior in online social systems

    Science.gov (United States)

    Grabowski, A.

    2009-06-01

    We present and study data concerning human behavior in four online social systems: (i) an Internet community of friends of over 107 people, (ii) a music community website with over 106 users, (iii) a gamers’ community server with over 5 × 106 users and (iv) a booklovers’ website with over 2.5 × 105 users. The purpose of those systems is different; however, their properties are very similar. We have found that the distribution of human activity (e.g., the sum of books read or songs played) has the form of a power law. Moreover, the relationship between human activity and time has a power-law form, too. We present a simple interest-driven model of the evolution of such systems which explains the emergence of two scaling regimes.

  17. Homeostatic modulation of stimulation-dependent plasticity in human motor cortex.

    Science.gov (United States)

    Ilić, N V; Milanović, S; Krstić, J; Bajec, D D; Grajić, M; Ilić, T V

    2011-01-01

    Since recently, it is possible, using noninvasive cortical stimulation, such as the protocol of paired associative stimulation (PAS), to induce the plastic changes in the motor cortex, in humans that mimic Hebb's model of learning. Application of TMS conjugated with peripheral electrical stimulation at strictly coherent temporal manner lead to convergence of inputs in the sensory-motor cortex, with the consequent synaptic potentiation or weakening, if applied repetitively. However, when optimal interstimulus interval (ISI) for induction of LTP-like effects is applied as a single pair, Motor evoked potential (MEP) amplitude inhibition is observed, the paradigm known as short-latency afferent inhibition (SLAI). Aiming to resolve this paradox, PAS protocols were applied, with 200 repetitions of TMS pulses paired with median nerve electrical stimulation, at ISI equal to individual latencies of evoked response of somatosensory cortex (N(20)) (PAS(LTP)), and at ISI of N(20) shortened for 5 msec (PAS(LTD)) - protocols that mimic LTP-like changes in the human motor cortex. MEP amplitudes before, during and after interventions were measured as an indicator based on output signals originating from the motor system. Post-intervention MEP amplitudes following the TMS protocols of PAS(LTP) and PAS(LTD) were facilitated and depressed, respectively, contrary to MEP amplitudes during intervention. During PAS(LTP) MEP amplitudes were significantly decreased in case of PAS(LTP), while in the case of PAS(LTD) an upward trend was observed. In conclusions, a possible explanation for the seemingly paradoxical effect of PAS can be found in the mechanism of homeostatic modulation of plasticity. Those findings indicate the existence of complex relationships in the development of plasticity induced by stimulation, depending on the level of the previous motor cortex excitability.

  18. Simultaneous atelectasis in human bocavirus infected monozygotic twins: was it plastic bronchitis?

    Science.gov (United States)

    Rüegger, Christoph M; Bär, Walter; Iseli, Peter

    2013-12-18

    Plastic bronchitis is an extremely rare disease characterized by the formation of tracheobronchial airway casts, which are composed of a fibrinous exudate with rubber-like consistency and cause respiratory distress as a result of severe airflow obstruction. Bronchial casts may be associated with congenital and acquired cardiopathies, bronchopulmonary diseases leading to mucus hypersecretion, and pulmonary lymphatic abnormalities. In recent years, however, there is growing evidence that plastic bronchitis can also be triggered by common respiratory tract infections and thereby cause atelectasis even in otherwise healthy children. We report on 22-month-old monozygotic twins presenting with atelectasis triggered by a simple respiratory tract infection. The clinical, laboratory, and radiographic findings given, bronchial cast formation was suspected in both infants but could only be confirmed after bronchoscopy in the first case. Real-time polymerase chain reaction of the removed cast as well as nasal lavage fluid of both infants demonstrated strong positivity for human bocavirus. Our case report is the first to describe two simultaneously affected monozygotic twins and substantiates the hypothesis of a contributing genetic factor in the pathophysiology of this disease. In this second report related to human bocavirus, we show additional evidence that this condition can be triggered by a simple respiratory tract infection in previously healthy infants.

  19. Visualization and Rule Validation in Human-Behavior Representation

    Science.gov (United States)

    Moya, Lisa Jean; McKenzie, Frederic D.; Nguyen, Quynh-Anh H.

    2008-01-01

    Human behavior representation (HBR) models simulate human behaviors and responses. The Joint Crowd Federate [TM] cognitive model developed by the Virginia Modeling, Analysis, and Simulation Center (VMASC) and licensed by WernerAnderson, Inc., models the cognitive behavior of crowds to provide credible crowd behavior in support of military…

  20. A model for plasticity kinetics and its role in simulating the dynamic behavior of Fe at high strain rates

    Energy Technology Data Exchange (ETDEWEB)

    Colvin, J D; Minich, R W; Kalantar, D H

    2007-03-29

    The recent diagnostic capability of the Omega laser to study solid-solid phase transitions at pressures greater than 10 GPa and at strain rates exceeding 10{sup 7} s{sup -1} has also provided valuable information on the dynamic elastic-plastic behavior of materials. We have found, for example, that plasticity kinetics modifies the effective loading and thermodynamic paths of the material. In this paper we derive a kinetics equation for the time-dependent plastic response of the material to dynamic loading, and describe the model's implementation in a radiation-hydrodynamics computer code. This model for plasticity kinetics incorporates the Gilman model for dislocation multiplication and saturation. We discuss the application of this model to the simulation of experimental velocity interferometry data for experiments on Omega in which Fe was shock compressed to pressures beyond the {alpha}-to-{var_epsilon} phase transition pressure. The kinetics model is shown to fit the data reasonably well in this high strain rate regime and further allows quantification of the relative contributions of dislocation multiplication and drag. The sensitivity of the observed signatures to the kinetics model parameters is presented.

  1. Two phase modeling of the influence of plastic strain on the magnetic and magnetostrictive behaviors of ferromagnetic materials

    Science.gov (United States)

    Hubert, Olivier; Lazreg, Said

    2017-02-01

    A growing interest of automotive industry in the use of high performance steels is observed. These materials are obtained thanks to complex manufacturing processes whose parameters fluctuations lead to strong variations of microstructure and mechanical properties. The on-line magnetic non-destructive monitoring is a relevant response to this problem but it requires fast models sensitive to different parameters of the forming process. The plastic deformation is one of these important parameters. Indeed, ferromagnetic materials are known to be sensitive to stress application and especially to plastic strains. In this paper, a macroscopic approach using the kinematic hardening is proposed to model this behavior, considering a plastic strained material as a two phase system. Relationship between kinematic hardening and residual stress is defined in this framework. Since stress fields are multiaxial, an uniaxial equivalent stress is calculated and introduced inside the so-called magneto-mechanical multidomain modeling to represent the effect of plastic strain. The modeling approach is complemented by many experiments involving magnetic and magnetostrictive measurements. They are carried out with or without applied stress, using a dual-phase steel deformed at different levels. The main interest of this material is that the mechanically hard phase, soft phase and the kinematic hardening can be clearly identified thanks to simple experiments. It is shown how this model can be extended to single phase materials.

  2. Mechanical Properties and Fracture Behavior of Cu-Co-Be Alloy after Plastic Deformation and Heat Treatment

    Institute of Scientific and Technical Information of China (English)

    Yan-jun ZHOU; Ke-xing SONG; Jian-dong XING; Zhou LI; Xiu-hua GUO

    2016-01-01

    Mechanical properties and fracture behavior of Cu-0.84Co-0.23Be alloy after plastic deformation and heat treatment were comparatively investigated.Severe plastic deformation by hot extrusion and cold drawing was adopted to induce large plastic strain of Cu-0.84Co-0.23Be alloy.The tensile strength and elongation are up to 476.6 MPa and 1 8%,respectively.The fractured surface consists of deep dimples and micro-voids.Due to the formation of su-persaturated solid solution on the Cu matrix by solution treatment at 950 ℃ for 1 h,the tensile strength decreased to 271.9 MPa,while the elongation increased to 42%.The fracture morphology is parabolic dimple.Furthermore,the tensile strength increased significantly to 580.2 MPa after aging at 480 ℃ for 4 h.During the aging process,a large number of precipitates formed and distributed on the Cu matrix.The fracture feature of aged specimens with low elongation (4.6%)exhibits an obvious brittle intergranular fracture.It is confirmed that the mechanical properties and fracture behavior are dominated by the microstructure characteristics of Cu-0.84Co-0.23Be alloy after plastic de-formation and heat treatment.In addition,the fracture behavior at 450 ℃ of aged Cu-0.84Co-0.23Be alloy was also studied.The tensile strength and elongation are 383.6 MPa and 11.2%,respectively.The fractured morphologies are mainly candy-shaped with partial parabolic dimples and equiaxed dimples.The fracture mode is multi-mixed mechanism that brittle intergranular fracture plays a dominant role and ductile fracture is secondary.

  3. Severe plastic deformation using friction stir processing, and the characterization of microstructure and mechanical behavior using neutron diffraction

    Science.gov (United States)

    Woo, Wanchuck

    Friction-stir welding (FSW) is a solid-state joining process, which utilizes a cylindrical rotating tool consisting of a concentric threaded tool pin and tool shoulder. The strong metallurgical bonding during the FSW is accomplished through: (1) the severe plastic deformation caused by the rotation of the tool pin that plunges into the material and travels along the joining line; and (2) the frictional heat generated mainly from the pressing tool shoulder. Recently, a number of variations of the FSW have been applied to modify the microstructure, for example, grain refinements and homogenization of precipitate particles, namely friction-stir processing (FSP). Applications of the FSP/FSW are widespread for the transportation industries. The microstructure and mechanical behavior of light-weight materials subjected to the FSW/FSP are being studied extensively. However, separating the effect of the frictional heat and severe plastic deformation on the residual stress and texture has been a standing problem for the fundamental understanding of FSW/FSP. The fundamental issues are: (i) the heat- and plastic-deformation-induced internal stresses that may be detrimental to the integrity and performance of components; (ii) the frictional heating that causes a microstructural softening due to the dissolution or growth of the precipitates in precipitation-hardenable Al alloys during the process; and (iii) the crystallographic texture can be significantly altered from the original texture, which could affect the physical and mechanical properties. The understanding of the influences of the de-convoluted sources (e.g. frictional heat, severe plastic deformation, or their combination) on the residual stress, microstructural softening, and texture variations during FSW can be used for a physicsvi based optimization of the processing parameters and new tool designs. Furthermore, the analyses and characterization of the natural aging behavior and the aging kinetics can be

  4. Th1/Th17 plasticity is a marker of advanced β cell autoimmunity and impaired glucose tolerance in humans

    NARCIS (Netherlands)

    Reinert-Hartwall, Linnea; Honkanen, Jarno; Salo, Harri M; Nieminen, Janne K; Luopajärvi, Kristiina; Härkönen, Taina; Veijola, Riitta; Simell, Olli; Ilonen, Jorma; Peet, Aleksandr; Tillmann, Vallo; Knip, Mikael; Vaarala, Outi; Harmsen, Hermanus

    2015-01-01

    Upregulation of IL-17 immunity and detrimental effects of IL-17 on human islets have been implicated in human type 1 diabetes. In animal models, the plasticity of Th1/Th17 cells contributes to the development of autoimmune diabetes. In this study, we demonstrate that the upregulation of the IL-17 pa

  5. Sympathetic nervous system behavior in human obesity.

    Science.gov (United States)

    Davy, Kevin P; Orr, Jeb S

    2009-02-01

    The sympathetic nervous system (SNS) plays an essential role in the regulation of metabolic and cardiovascular homeostasis. Low SNS activity has been suggested to be a risk factor for weight gain and obesity development. In contrast, SNS activation is characteristic of a number of metabolic and cardiovascular diseases that occur more frequently in obese individuals. Until recently, the relation between obesity and SNS behavior has been controversial because previous approaches for assessing SNS activity in humans have produced inconsistent findings. Beginning in the early 1990s, many studies using state of the art neurochemical and neurophysiological techniques have provided important insight. The purpose of the present review is to provide an overview of our current understanding of the region specific alterations in SNS behavior in human obesity. We will discuss findings from our own laboratory which implicate visceral fat as an important depot linking obesity with skeletal muscle SNS activation. The influence of weight change on SNS behavior and the potential mechanisms and consequences of region specific SNS activation in obesity will also be considered.

  6. Bridging animal and human models of exercise-induced brain plasticity

    Science.gov (United States)

    Voss, Michelle W.; Vivar, Carmen; Kramer, Arthur F.; van Praag, Henriette

    2015-01-01

    Significant progress has been made in understanding the neurobiological mechanisms through which exercise protects and restores the brain. In this feature review, we integrate animal and human research, examining physical activity effects across multiple levels of description (neurons up to inter-regional pathways). We evaluate the influence of exercise on hippocampal structure and function, addressing common themes such as spatial memory and pattern separation, brain structure and plasticity, neurotrophic factors, and vasculature. Areas of research focused more within species, such as hippocampal neurogenesis in rodents, also provide crucial insight into the protective role of physical activity. Overall, converging evidence suggests exercise benefits brain function and cognition across the mammalian lifespan, which may translate into reduced risk for Alzheimer’s disease (AD) in humans. PMID:24029446

  7. Bridging animal and human models of exercise-induced brain plasticity.

    Science.gov (United States)

    Voss, Michelle W; Vivar, Carmen; Kramer, Arthur F; van Praag, Henriette

    2013-10-01

    Significant progress has been made in understanding the neurobiological mechanisms through which exercise protects and restores the brain. In this feature review, we integrate animal and human research, examining physical activity effects across multiple levels of description (neurons up to inter-regional pathways). We evaluate the influence of exercise on hippocampal structure and function, addressing common themes such as spatial memory and pattern separation, brain structure and plasticity, neurotrophic factors, and vasculature. Areas of research focused more within species, such as hippocampal neurogenesis in rodents, also provide crucial insight into the protective role of physical activity. Overall, converging evidence suggests exercise benefits brain function and cognition across the mammalian lifespan, which may translate into reduced risk for Alzheimer's disease (AD) in humans.

  8. Oxytocin and Maternal Brain Plasticity

    Science.gov (United States)

    Kim, Sohye; Strathearn, Lane

    2016-01-01

    Although dramatic postnatal changes in maternal behavior have long been noted, we are only now beginning to understand the neurobiological mechanisms that support this transition. The present paper synthesizes growing insights from both animal and human research to provide an overview of the plasticity of the mother's brain, with a particular…

  9. Spinal Plasticity and Behavior: BDNF-Induced Neuromodulation in Uninjured and Injured Spinal Cord

    Directory of Open Access Journals (Sweden)

    Sandra M. Garraway

    2016-01-01

    Full Text Available Brain-derived neurotrophic factor (BDNF is a member of the neurotrophic factor family of signaling molecules. Since its discovery over three decades ago, BDNF has been identified as an important regulator of neuronal development, synaptic transmission, and cellular and synaptic plasticity and has been shown to function in the formation and maintenance of certain forms of memory. Neural plasticity that underlies learning and memory in the hippocampus shares distinct characteristics with spinal cord nociceptive plasticity. Research examining the role BDNF plays in spinal nociception and pain overwhelmingly suggests that BDNF promotes pronociceptive effects. BDNF induces synaptic facilitation and engages central sensitization-like mechanisms. Also, peripheral injury-induced neuropathic pain is often accompanied with increased spinal expression of BDNF. Research has extended to examine how spinal cord injury (SCI influences BDNF plasticity and the effects BDNF has on sensory and motor functions after SCI. Functional recovery and adaptive plasticity after SCI are typically associated with upregulation of BDNF. Although neuropathic pain is a common consequence of SCI, the relation between BDNF and pain after SCI remains elusive. This article reviews recent literature and discusses the diverse actions of BDNF. We also highlight similarities and differences in BDNF-induced nociceptive plasticity in naïve and SCI conditions.

  10. Direct-current-dependent shift of theta-burst-induced plasticity in the human motor cortex.

    Science.gov (United States)

    Hasan, Alkomiet; Hamada, Masashi; Nitsche, Michael A; Ruge, Diane; Galea, Joseph M; Wobrock, Thomas; Rothwell, John C

    2012-03-01

    Animal studies using polarising currents have shown that induction of synaptic long-term potentiation (LTP) and long-term depression (LTD) by bursts of patterned stimulation is affected by the membrane potential of the postsynaptic neurone. The aim of the present experiments was to test whether it is possible to observe similar phenomena in humans with the aim of improving present protocols of inducing synaptic plasticity for therapeutic purposes. We tested whether the LTP/LTD-like after effects of transcranial theta-burst stimulation (TBS) of human motor cortex, an analogue of patterned electrical stimulation in animals, were affected by simultaneous transcranial direct-current stimulation (tDCS), a non-invasive method of polarising cortical neurones in humans. Nine healthy volunteers were investigated in a single-blind, balanced cross-over study; continuous TBS (cTBS) was used to introduce LTD-like after effects, whereas intermittent TBS (iTBS) produced LTP-like effects. Each pattern was coupled with concurrent application of tDCS (motor thresholds and intracortical inhibitory/facilitatory networks were not altered by any of the stimulation protocols. We conclude that the after effects of TBS can be modulated by concurrent tDCS. We hypothesise that tDCS changes the membrane potential of the apical dendrites of cortical pyramidal neurones and that this changes the response to patterned synaptic input evoked by TBS. The data show that it may be possible to enhance LTP-like plasticity after TBS in the human cortex.

  11. Mitigating Insider Threat Using Human Behavior Influence Models

    Science.gov (United States)

    2006-06-01

    Change in Score Versus Time for Both Employees (over 3 years).......................94 45. Distribution of Sensitivity Tests Performed ...Human Behavior Human Behavior is defined as a “collection of activities performed by human beings and influenced by culture, attitudes, emotions...values, ethics, authority, rapport, hypnosis , persuasion, and/or coercion.” [6] The theory behind human behavior is humans react to “definite objective

  12. Human brain plasticity: evidence from sensory deprivation and altered language experience.

    Science.gov (United States)

    Neville, Helen; Bavelier, Daphne

    2002-01-01

    The results from the language studies taken as a whole point to different developmental time courses and developmental vulnerabilities of aspects of grammatical and semantic/lexical processing. They thus provide support for conceptions of language that distinguish these subprocesses within language. Similarly, following auditory deprivation, processes associated with the dorsal visual pathway were more altered than were functions associated with the ventral pathway, providing support for conceptions of visual system organization that distinguish functions along these lines. Could the effects observed in blind and deaf adults be accounted for, at least in part, by the redundant connectivity of the immature human brain? One way we tested this hypothesis was to study the differentiation of visual and auditory sensory responses in normal development (Neville, 1995). In normal adults, auditory stimuli elicit ERP responses that are large over temporal brain regions but small or absent over occipital regions. By contrast, in 6-month-old children we observed that auditory ERPs are equally large over temporal and visual brain regions, consistent with the idea that there is less specificity and more redundancy of connections between the auditory and visual cortex at this time. Between 6 and 36 months, however, we observed a gradual decrease in the amplitude of the auditory ERP over visual areas, while the amplitude over the temporal areas was unchanged. These results suggest that early in human development, there exists a redundancy of connections between auditory and visual areas and that this overlap gradually decreases after birth. This loss of redundancy may be a boundary condition that determines when sensory deprivation can result in alterations in the organization of remaining sensory systems. The considerable variability in timing of sensitive periods may also be in part due to temporal differences in the occurrence of redundancy within different systems. Ongoing

  13. Inactivation of BRD7 results in impaired cognitive behavior and reduced synaptic plasticity of the medial prefrontal cortex.

    Science.gov (United States)

    Xu, Yang; Cao, Wenyu; Zhou, Ming; Li, Changqi; Luo, Yanwei; Wang, Heran; Zhao, Ran; Jiang, Shihe; Yang, Jing; Liu, Yukun; Wang, Xinye; Li, Xiayu; Xiong, Wei; Ma, Jian; Peng, Shuping; Zeng, Zhaoyang; Li, Xiaoling; Tan, Ming; Li, Guiyuan

    2015-06-01

    BRD7 is a bromodomain-containing protein (BCP), and recent evidence implicates the role of BCPs in the initiation and development of neurodevelopmental disorders. However, few studies have investigated the biological functions of BRD7 in the central nervous system. In our study, BRD7 was found to be widely expressed in various regions of the mouse brain, including the medial prefrontal cortex (mPFC), caudate putamen (CPu), hippocampus (Hip), midbrain (Mb), cerebellum (Cb), and mainly co-localized with neuron but not with glia. Using a BRD7 knockout mouse model and a battery of behavioral tests, we report that disruption of BRD7 results in impaired cognitive behavior leaving the emotional behavior unaffected. Moreover, a series of proteins involved in synaptic plasticity were decreased in the medial prefrontal cortex and there was a concomitant decrease in neuronal spine density and dendritic branching in the medial prefrontal cortex. However, no significant difference was found in the hippocampus compared to the wild-type mice. Thus, BRD7 might play a critical role in the regulation of synaptic plasticity and affect cognitive behavior.

  14. Plasticity of the intrinsic period of the human circadian timing system.

    Directory of Open Access Journals (Sweden)

    Frank A J L Scheer

    Full Text Available Human expeditions to Mars will require adaptation to the 24.65-h Martian solar day-night cycle (sol, which is outside the range of entrainment of the human circadian pacemaker under lighting intensities to which astronauts are typically exposed. Failure to entrain the circadian time-keeping system to the desired rest-activity cycle disturbs sleep and impairs cognitive function. Furthermore, differences between the intrinsic circadian period and Earth's 24-h light-dark cycle underlie human circadian rhythm sleep disorders, such as advanced sleep phase disorder and non-24-hour sleep-wake disorders. Therefore, first, we tested whether exposure to a model-based lighting regimen would entrain the human circadian pacemaker at a normal phase angle to the 24.65-h Martian sol and to the 23.5-h day length often required of astronauts during short duration space exploration. Second, we tested here whether such prior entrainment to non-24-h light-dark cycles would lead to subsequent modification of the intrinsic period of the human circadian timing system. Here we show that exposure to moderately bright light ( approximately 450 lux; approximately 1.2 W/m(2 for the second or first half of the scheduled wake episode is effective for entraining individuals to the 24.65-h Martian sol and a 23.5-h day length, respectively. Estimations of the circadian periods of plasma melatonin, plasma cortisol, and core body temperature rhythms collected under forced desynchrony protocols revealed that the intrinsic circadian period of the human circadian pacemaker was significantly longer following entrainment to the Martian sol as compared to following entrainment to the 23.5-h day. The latter finding of after-effects of entrainment reveals for the first time plasticity of the period of the human circadian timing system. Both findings have important implications for the treatment of circadian rhythm sleep disorders and human space exploration.

  15. Human intermittent hypoxia-induced respiratory plasticity is not caused by inflammation.

    Science.gov (United States)

    Beaudin, Andrew E; Waltz, Xavier; Pun, Matiram; Wynne-Edwards, Katherine E; Ahmed, Sofia B; Anderson, Todd J; Hanly, Patrick J; Poulin, Marc J

    2015-10-01

    Ventilatory instability, reflected by enhanced acute hypoxic (AHVR) and hypercapnic (AHCVR) ventilatory responses is a fundamental component of obstructive sleep apnoea (OSA) pathogenesis. Intermittent hypoxia-induced inflammation is postulated to promote AHVR enhancement in OSA, although the role of inflammation in intermittent hypoxia-induced respiratory changes in humans has not been examined. Thus, this study assessed the role of inflammation in intermittent hypoxia-induced respiratory plasticity in healthy humans.In a double-blind, placebo-controlled, randomised crossover study design, 12 males were exposed to 6 h of intermittent hypoxia on three occasions. Prior to intermittent hypoxia exposures, participants ingested (for 4  days) either placebo or the nonsteroidal anti-inflammatory drugs indomethacin (nonselective cyclooxygenase (COX) inhibitor) and celecoxib (selective COX-2 inhibitor). Pre- and post-intermittent hypoxia resting ventilation, AHVR, AHCVR and serum concentration of the pro-inflammatory cytokine tumour necrosis factor (TNF)-α were assessed.Pre-intermittent hypoxia resting ventilation, AHVR, AHCVR and TNF-α concentrations were similar across all three conditions (p≥0.093). Intermittent hypoxia increased resting ventilation and the AHVR similarly across all conditions (p=0.827), while the AHCVR was increased (p=0.003) and TNF-α was decreased (p=0.006) with only selective COX-2 inhibition.These findings indicate that inflammation does not contribute to human intermittent hypoxia-induced respiratory plasticity. Moreover, selective COX-2 inhibition augmented the AHCVR following intermittent hypoxia exposure, suggesting that selective COX-2 inhibition could exacerbate OSA severity by increasing ventilatory instability.

  16. Regional-specific effects of ovarian hormone loss on synaptic plasticity in adult human APOE targeted replacement mice.

    Directory of Open Access Journals (Sweden)

    Rebecca C Klein

    Full Text Available The human apolipoprotein ε4 allele (APOE4 has been implicated as one of the strongest genetic risk factors associated with Alzheimer's disease (AD and in influencing normal cognitive functioning. Previous studies have demonstrated that mice expressing human apoE4 display deficits in behavioral and neurophysiological outcomes compared to those with apoE3. Ovarian hormones have also been shown to be important in modulating synaptic processes underlying cognitive function, yet little is known about how their effects are influenced by apoE. In the current study, female adult human APOE targeted replacement (TR mice were utilized to examine the effects of human APOE genotype and long-term ovarian hormone loss on synaptic plasticity in limbic regions by measuring dendritic spine density and electrophysiological function. No significant genotype differences were observed on any outcomes within intact mice. However, there was a significant main effect of genotype on total spine density in apical dendrites in the hippocampus, with post-hoc t-tests revealing a significant reduction in spine density in apoE3 ovariectomized (OVX mice compared to sham operated mice. There was also a significant main effect of OVX on the magnitude of LTP, with post-hoc t-tests revealing a decrease in apoE3 OVX mice relative to sham. In contrast, apoE4 OVX mice showed increased synaptic activity relative to sham. In the lateral amygdala, there was a significant increase in total spine density in apoE4 OVX mice relative to sham. This increase in spine density was consistent with a significant increase in spontaneous excitatory activity in apoE4 OVX mice. These findings suggest that ovarian hormones differentially modulate synaptic integrity in an apoE-dependent manner within brain regions that are susceptible to neurophysiological dysfunction associated with AD.

  17. Synaptic dysfunction in human immunodeficiency virus type-1-positive subjects: inflammation or impaired neuronal plasticity?

    Science.gov (United States)

    Avdoshina, Valeriya; Bachis, Alessia; Mocchetti, Italo

    2013-01-01

    Many people infected with the human immunodeficiency virus type-1 (HIV) exhibit mild or severe neurological problems, termed HIV-associated neurocognitive disorder (HAND), even when receiving antiretroviral therapy. Thus, novel adjunctive therapies must be developed to overcome the neurotoxic effect of HIV. New therapies require a better understanding of the molecular and cellular mechanisms of HIV-induced neurotoxicity and the risk factors that, besides inflammation and T cell depletion and drugs of abuse, render the central nervous system (CNS) a target of HIV-induced neurotoxicity. HIV appears to impair neuronal plasticity, which refers to the innate ability of the CNS to respond to injury and promote recovery of function. The availability of brain-derived neurotrophic factor (BDNF), a potent neurotrophic factor that is present in abundance in the adult brain, is essential for neuronal plasticity. BDNF acts through a receptor system composed of Trk and p75NTR. Here we present experimental evidence that some of the clinical features of HIV-mediated neurological impairment could result from altered BDNF/TrkB/p75NTR regulation and function. PMID:23600400

  18. Consciousness, plasticity, and connectomics: the role of intersubjectivity in human cognition.

    Science.gov (United States)

    Allen, Micah; Williams, Gary

    2011-01-01

    Consciousness is typically construed as being explainable purely in terms of either private, raw feels or higher-order, reflective representations. In contrast to this false dichotomy, we propose a new view of consciousness as an interactive, plastic phenomenon open to sociocultural influence. We take up our account of consciousness from the observation of radical cortical neuroplasticity in human development. Accordingly, we draw upon recent research on macroscopic neural networks, including the "default mode," to illustrate cases in which an individual's particular "connectome" is shaped by encultured social practices that depend upon and influence phenomenal and reflective consciousness. On our account, the dynamically interacting connectivity of these networks bring about important individual differences in conscious experience and determine what is "present" in consciousness. Further, we argue that the organization of the brain into discrete anti-correlated networks supports the phenomenological distinction of prereflective and reflective consciousness, but we emphasize that this finding must be interpreted in light of the dynamic, category-resistant nature of consciousness. Our account motivates philosophical and empirical hypotheses regarding the appropriate time-scale and function of neuroplastic adaptation, the relation of high and low-frequency neural activity to consciousness and cognitive plasticity, and the role of ritual social practices in neural development and cognitive function.

  19. Study of Reactive Melt Processing Behavior of Externally Plasticized Cellulose Acetate in Presence of Isocyanate

    Directory of Open Access Journals (Sweden)

    Rafael Erdmann

    2014-12-01

    Full Text Available Two types of externally plasticized cellulose acetate (CA were chemically modified using 4,4'-methylene diphenyl diisocyanate (MDI as crosslinking agent. Crosslinking was performed in the molten state by means of melt mixing in an internal mixer. The viscoelastic properties of the non-crosslinked, externally plasticized CA show typical temperature dependence, similar to conventional thermoplastics. A strong increase in storage modulus is observed with increasing crosslink density indicating that the crosslinked compounds exhibit predominately elastic response. The complex viscosity also increases considerably with increasing crosslink density and does not reach the typical Newtonian plateau at low radial frequencies any more. The viscoelastic properties correlate well with the data recorded online during reactive melt processing in the internal mixer. In comparison to the non-crosslinked CA, the crosslinked compounds show higher glass transition temperature, higher VICAT softening temperatures, improved thermal stability and lower plasticizer evaporation at evaluated temperatures.

  20. Anomalous human behavior detection: an adaptive approach

    Science.gov (United States)

    van Leeuwen, Coen; Halma, Arvid; Schutte, Klamer

    2013-05-01

    Detection of anomalies (outliers or abnormal instances) is an important element in a range of applications such as fault, fraud, suspicious behavior detection and knowledge discovery. In this article we propose a new method for anomaly detection and performed tested its ability to detect anomalous behavior in videos from DARPA's Mind's Eye program, containing a variety of human activities. In this semi-unsupervised task a set of normal instances is provided for training, after which unknown abnormal behavior has to be detected in a test set. The features extracted from the video data have high dimensionality, are sparse and inhomogeneously distributed in the feature space making it a challenging task. Given these characteristics a distance-based method is preferred, but choosing a threshold to classify instances as (ab)normal is non-trivial. Our novel aproach, the Adaptive Outlier Distance (AOD) is able to detect outliers in these conditions based on local distance ratios. The underlying assumption is that the local maximum distance between labeled examples is a good indicator of the variation in that neighborhood, and therefore a local threshold will result in more robust outlier detection. We compare our method to existing state-of-art methods such as the Local Outlier Factor (LOF) and the Local Distance-based Outlier Factor (LDOF). The results of the experiments show that our novel approach improves the quality of the anomaly detection.

  1. The plasticity of human breast carcinoma cells is more than epithelial to mesenchymal conversion

    DEFF Research Database (Denmark)

    Petersen, Ole William; Nielsen, Helga Lind; Gudjonsson, Thorarinn;

    2001-01-01

    The human breast comprises three lineages: the luminal epithelial lineage, the myoepithelial lineage, and the mesenchymal lineage. It has been widely accepted that human breast neoplasia pertains only to the luminal epithelial lineage. In recent years, however, evidence has accumulated that neopl......The human breast comprises three lineages: the luminal epithelial lineage, the myoepithelial lineage, and the mesenchymal lineage. It has been widely accepted that human breast neoplasia pertains only to the luminal epithelial lineage. In recent years, however, evidence has accumulated...... that neoplastic breast epithelial cells may be substantially more plastic in their differentiation repertoire than previously anticipated. Thus, along with an increasing availability of markers for the myoepithelial lineage, at least a partial differentiation towards this lineage is being revealed frequently....... It has also become clear that conversions towards the mesenchymal lineage actually occur, referred to as epithelial to mesenchymal transitions. Indeed, some of the so-called myofibroblasts surrounding the tumor may have an epithelial origin rather than a mesenchymal origin. Because myoepithelial cells...

  2. Elasto-Plastic Constitutive Behavior in Three Lithofacies of the Cambrian Mt. Simon Sandstone, Illinois Basin, USA

    Science.gov (United States)

    Dewers, T.; Newell, P.; Broome, S. T.; Heath, J. E.; Bauer, S. J.

    2012-12-01

    The Mt. Simon Formation, a basal Cambrian sandstone underlying the Illinois Basin in the Central US, is a target for underground storage and waste injection which require an assessment of geomechanical behavior. The range of depositional environments, from braided streams and minor eolean features in the lower Mt Simon, to tidally-influenced near- and on-shore sands in the upper Mt. Simon, yield a heterogeneous formation with a range in porosity, permeability, and mechanical properties. We examine the experimental deformational behavior of three distinct Mt. Simon lithofacies via axisymmetric compressional testing. Initial yielding is confirmed with acoustic emissions in many of the tests and failure envelopes are determined for each lithofacies. The evolution of (assumed) isotropic elastic moduli are examined during testing by use of unload-reload cycles, which permit the separation of total measured strains into elastic and plastic (permanent) strains. The upper Mt Simon samples deform largely elastically at stresses encountered in the Illinois Basin, with very little modulus degradation. The lower Mt. Simon facies are weaker and deform plastically, with varying amounts of modulus degradation. Results are interpreted via petrographic observation of textural contrasts. This range in constitutive response is captured up to failure with a phenomenological elasto-plasticity model. Essential aspects to describe observed behavior used in the model include non-associative plasticity, stress-invariant dependent failure, an elliptical cap surface capturing shear effects on pore collapse, kinematic and isotropic hardening, nonlinear elasticity and elastic-plastic coupling, among other features. Static moduli derived from laboratory tests are compared to dynamic moduli from wellbore log response which can allow experimental results and model to be extrapolated to Mt. Simon occurrences across the basin. This work was funded in part by the Center for Frontiers of Subsurface

  3. Phenotypic plasticity: molecular mechanisms and adaptive significance.

    Science.gov (United States)

    Kelly, Scott A; Panhuis, Tami M; Stoehr, Andrew M

    2012-04-01

    Phenotypic plasticity can be broadly defined as the ability of one genotype to produce more than one phenotype when exposed to different environments, as the modification of developmental events by the environment, or as the ability of an individual organism to alter its phenotype in response to changes in environmental conditions. Not surprisingly, the study of phenotypic plasticity is innately interdisciplinary and encompasses aspects of behavior, development, ecology, evolution, genetics, genomics, and multiple physiological systems at various levels of biological organization. From an ecological and evolutionary perspective, phenotypic plasticity may be a powerful means of adaptation and dramatic examples of phenotypic plasticity include predator avoidance, insect wing polymorphisms, the timing of metamorphosis in amphibians, osmoregulation in fishes, and alternative reproductive tactics in male vertebrates. From a human health perspective, documented examples of plasticity most commonly include the results of exercise, training, and/or dieting on human morphology and physiology. Regardless of the discipline, phenotypic plasticity has increasingly become the target of a plethora of investigations with the methodological approaches utilized ranging from the molecular to whole organsimal. In this article, we provide a brief historical outlook on phenotypic plasticity; examine its potential adaptive significance; emphasize recent molecular approaches that provide novel insight into underlying mechanisms, and highlight examples in fishes and insects. Finally, we highlight examples of phenotypic plasticity from a human health perspective and underscore the use of mouse models as a powerful tool in understanding the genetic architecture of phenotypic plasticity.

  4. Habits, habitats, and heredity: a brief history of studies in human plasticity.

    Science.gov (United States)

    Hulse, F S

    1981-12-01

    There has long been controversy concerning the relative importance of environment and ancestry in determining the characteristics of living creatures including members of the human species. At the beginning of the present century most biologists and anthropologists seem to have assumed that environment had little or no effect upon our bodily traits. We inherited them. The studies of Franz Boas on Changes in bodily Form of Descendants of Immigrants cast doubts upon this assumption, and provoked considerable resentment. Since 1911, however, quite a few scholars have confirmed and elaborated upon the findings of Boas. At the same time, many other studies have demonstrated secular changes in bodily size and shape within quite a few different populations. The idea of bodily plasticity has therefore, by this decade, become quite acceptable. This paper recounts the historical sequence of events leading to the change in anthropological assumptions, mentioning the scholars whose work contributed to this important advance in scientific understanding.

  5. Homeostatic plasticity in human motor cortex demonstrated by two consecutive sessions of paired associative stimulation.

    Science.gov (United States)

    Müller, J Florian M; Orekhov, Yuriy; Liu, Yali; Ziemann, Ulf

    2007-06-01

    Long-term potentiation (LTP) and long-term depression (LTD) underlie most models of learning and memory, but neural activity would grow or shrink in an uncontrolled manner, if not guarded by stabilizing mechanisms. The Bienenstock-Cooper-Munro (BCM) rule proposes a sliding threshold for LTP/LTD induction: LTP induction becomes more difficult if neural activity was high previously. Here we tested if this form of homeostatic plasticity applies to the human motor cortex (M1) in vivo by examining the interactions between two consecutive sessions of paired associative stimulation (PAS). PAS consisted of repeated pairs of electrical stimulation of the right median nerve followed by transcranial magnetic stimulation of the left M1. The first PAS session employed an interstimulus interval equalling the individual N20-latency of the median nerve somatosensory-evoked cortical potential plus 2 ms, N20-latency minus 5 ms, or a random alternation between these intervals, to induce an LTP-like increase in motor-evoked potential (MEP) amplitudes in the right abductor pollicis brevis muscle (PAS(LTP)), an LTD-like decrease (PAS(LTD)), or no change (PAS(Control)), respectively. The second PAS session 30 min later was always PAS(LTP). It induced an moderate LTP-like effect if conditioned by PAS(Control), which increased if conditioned by PAS(LTD), but decreased if conditioned by PAS(LTP). Effects on MEP amplitude induced by the second PAS session exhibited a negative linear correlation with those in the first PAS session. Because the two PAS sessions activate identical neuronal circuits, we conclude that 'homosynaptic-like' homeostatic mechanisms in accord with the BCM rule contribute to regulating plasticity in human M1.

  6. Synergistic Effects of Nucleating Agents and Plasticizers on the Crystallization Behavior of Poly(lactic acid

    Directory of Open Access Journals (Sweden)

    Xuetao Shi

    2015-01-01

    Full Text Available The synergistic effect of nucleating agents and plasticizers on the thermal and mechanical performance of PLA nanocomposites was investigated with the objective of increasing the crystallinity and balancing the stiffness and toughness of PLA mechanical properties. Calcium carbonate, halloysite nanotubes, talc and LAK (sulfates were compared with each other as heterogeneous nucleating agents. Both the DSC isothermal and non-isothermal studies indicated that talc and LAK were the more effective nucleating agents among the selected fillers. Poly(D-lactic acid (PDLA acted also as a nucleating agent due to the formation of the PLA stereocomplex. The half crystallization time was reduced by the addition of talc to about 2 min from 37.5 min of pure PLA by the isothermal crystallization study. The dynamic mechanical thermal study (DMTA indicated that nanofillers acted as both reinforcement fillers and nucleating agents in relation to the higher storage modulus. The plasticized PLA studied by DMTA indicated a decreasing glass transition temperature with the increasing of the PEG content. The addition of nanofiller increased the Young’s modulus. PEG had the plasticization effect of increasing the break deformation, while sharply decreasing the stiffness and strength of PLA. The synergistic effect of nanofillers and plasticizer achieved the balance between stiffness and toughness with well-controlled crystallization.

  7. Thermal behavior of epoxidized cardanol diethyl phosphate as novel renewable plasticizer for poly(vinyl chloride)

    Science.gov (United States)

    A novel plasticizer, epoxidized cardanol diethyl phosphate (ECEP), based on cardanol was synthesized. Chemical structure of ECEP was characterized by fourier transform infrared (FTIR), 1H-nuclear magnetic resonance(1H NMR) and 13C-nuclear magnetic resonance(13C NMR) spectroscopy. Effects of ECEP sub...

  8. Effect of r-value and texture on plastic deformation and necking behavior in interstitial-free steel sheets

    Science.gov (United States)

    Oh, Gyu-Jin; Lee, Kye-Man; Huh, Moo-Young; Park, Jin Eon; Park, Soo Ho; Engler, Olaf

    2017-01-01

    Three initial tensile specimens having different textures and, in consequence, different r-values were cut from a sheet of an interstitial-free steel. Using these specimens, the effect of r-value and texture on plastic deformation and the necking behavior were studied by tackling the strain state and texture during tensile tests. A reduced decrease in work hardening rate of tensile specimens with higher r-values led to a slower onset of diffuse necking which offers an increased uniform elongation. A slower reduction in thickness of specimens with a higher r-value provided a favorable resistance against onset of failure by localized necking.

  9. Finite deformation analysis of continuum structures with time dependent anisotropic elastic plastic material behavior (LWBR/AWBA Development Program)

    Energy Technology Data Exchange (ETDEWEB)

    Hutula, D.N.

    1980-03-01

    A finite element procedure is presented for finite deformation analysis of continuum structures with time-dependent anisotropic elastic-plastic material behavior. An updated Lagrangian formulation is used to describe the kinematics of deformation. Anisotropic constitutive relations are referred, at each material point, to a set of three mutually orthogonal axes which rotate as a unit with an angular velocity equal to the spin at the point. The time-history of the solution is generated by using a linear incremental procedure with residual force correction, along with an automatic time step control algorithm which chooses time step sizes to control the accuracy and numerical stability of the solution.

  10. Elasto-plasticity and pore-pressure coupled analysis on the pullout behaviors of a plate anchor

    Directory of Open Access Journals (Sweden)

    Cun Hu

    2015-03-01

    Full Text Available A numerical method is proposed for the elasto-plasticity and pore-pressure coupled analysis on the pullout behaviors of a plate anchor. The bounding-surface plasticity (BSP model combined with Biot’s consolidation theory is employed to simulate the cyclic loading induced elasto-plastic deformation of the soil skeleton and the accompanying generation/dissipation of the excess pore water pressure. The suction force generated around the anchor due to the cyclic variation of the pore water pressure has much effect on the pullout capacity of the plate anchor. The calculated pullout capacity with the proposed method (i.e., the coupled analysis gets lower than that with the conventional total stress analysis for the case of long-term sustained loading, but slightly higher for the case of short-term monotonic loading. The cyclic loading induced accumulation of pore water pressure may result in an obvious decrease of the stiffness of the soil-plate anchor system.

  11. Increased Expression of the PI3K Enhancer PIKE Mediates Deficits in Synaptic Plasticity and Behavior in Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    Christina Gross

    2015-05-01

    Full Text Available The PI3K enhancer PIKE links PI3K catalytic subunits to group 1 metabotropic glutamate receptors (mGlu1/5 and activates PI3K signaling. The roles of PIKE in synaptic plasticity and the etiology of mental disorders are unknown. Here, we show that increased PIKE expression is a key mediator of impaired mGlu1/5-dependent neuronal plasticity in mouse and fly models of the inherited intellectual disability fragile X syndrome (FXS. Normalizing elevated PIKE protein levels in FXS mice reversed deficits in molecular and cellular plasticity and improved behavior. Notably, PIKE reduction rescued PI3K-dependent and -independent neuronal defects in FXS. We further show that PI3K signaling is increased in a fly model of FXS and that genetic reduction of the Drosophila ortholog of PIKE, CenG1A rescued excessive PI3K signaling, mushroom body defects, and impaired short-term memory in these flies. Our results demonstrate a crucial role of increased PIKE expression in exaggerated mGlu1/5 signaling causing neuronal defects in FXS.

  12. Increased expression of the PI3K enhancer PIKE mediates deficits in synaptic plasticity and behavior in fragile X syndrome.

    Science.gov (United States)

    Gross, Christina; Chang, Chia-Wei; Kelly, Seth M; Bhattacharya, Aditi; McBride, Sean M J; Danielson, Scott W; Jiang, Michael Q; Chan, Chi Bun; Ye, Keqiang; Gibson, Jay R; Klann, Eric; Jongens, Thomas A; Moberg, Kenneth H; Huber, Kimberly M; Bassell, Gary J

    2015-05-05

    The PI3K enhancer PIKE links PI3K catalytic subunits to group 1 metabotropic glutamate receptors (mGlu1/5) and activates PI3K signaling. The roles of PIKE in synaptic plasticity and the etiology of mental disorders are unknown. Here, we show that increased PIKE expression is a key mediator of impaired mGlu1/5-dependent neuronal plasticity in mouse and fly models of the inherited intellectual disability fragile X syndrome (FXS). Normalizing elevated PIKE protein levels in FXS mice reversed deficits in molecular and cellular plasticity and improved behavior. Notably, PIKE reduction rescued PI3K-dependent and -independent neuronal defects in FXS. We further show that PI3K signaling is increased in a fly model of FXS and that genetic reduction of the Drosophila ortholog of PIKE, CenG1A rescued excessive PI3K signaling, mushroom body defects, and impaired short-term memory in these flies. Our results demonstrate a crucial role of increased PIKE expression in exaggerated mGlu1/5 signaling causing neuronal defects in FXS.

  13. Plasticity of adult human pancreatic duct cells by neurogenin3-mediated reprogramming.

    Directory of Open Access Journals (Sweden)

    Nathalie Swales

    Full Text Available AIMS/HYPOTHESIS: Duct cells isolated from adult human pancreas can be reprogrammed to express islet beta cell genes by adenoviral transduction of the developmental transcription factor neurogenin3 (Ngn3. In this study we aimed to fully characterize the extent of this reprogramming and intended to improve it. METHODS: The extent of the Ngn3-mediated duct-to-endocrine cell reprogramming was measured employing genome wide mRNA profiling. By modulation of the Delta-Notch signaling or addition of pancreatic endocrine transcription factors Myt1, MafA and Pdx1 we intended to improve the reprogramming. RESULTS: Ngn3 stimulates duct cells to express a focused set of genes that are characteristic for islet endocrine cells and/or neural tissues. This neuro-endocrine shift however, is incomplete with less than 10% of full duct-to-endocrine reprogramming achieved. Transduction of exogenous Ngn3 activates endogenous Ngn3 suggesting auto-activation of this gene. Furthermore, pancreatic endocrine reprogramming of human duct cells can be moderately enhanced by inhibition of Delta-Notch signaling as well as by co-expressing the transcription factor Myt1, but not MafA and Pdx1. CONCLUSIONS/INTERPRETATION: The results provide further insight into the plasticity of adult human duct cells and suggest measurable routes to enhance Ngn3-mediated in vitro reprogramming protocols for regenerative beta cell therapy in diabetes.

  14. Th1/Th17 Plasticity Is a Marker of Advanced β Cell Autoimmunity and Impaired Glucose Tolerance in Humans

    Science.gov (United States)

    Reinert-Hartwall, Linnea; Honkanen, Jarno; Salo, Harri M.; Nieminen, Janne K.; Luopajärvi, Kristiina; Härkönen, Taina; Veijola, Riitta; Simell, Olli; Ilonen, Jorma; Peet, Aleksandr; Tillmann, Vallo; Knip, Mikael; Knip, Mikael; Koski, Katriina; Koski, Matti; Härkönen, Taina; Ryhänen, Samppa; Hämäläinen, Anu-Maaria; Ormisson, Anne; Peet, Aleksandr; Tillmann, Vallo; Ulich, Valentina; Kuzmicheva, Elena; Mokurov, Sergei; Markova, Svetlana; Pylova, Svetlana; Isakova, Marina; Shakurova, Elena; Petrov, Vladimir; Dorshakova, Natalya V.; Karapetyan, Tatyana; Varlamova, Tatyana; Ilonen, Jorma; Kiviniemi, Minna; Alnek, Kristi; Janson, Helis; Uibo, Raivo; Salum, Tiit; von Mutius, Erika; Weber, Juliane; Ahlfors, Helena; Kallionpää, Henna; Laajala, Essi; Lahesmaa, Riitta; Lähdesmäki, Harri; Moulder, Robert; Nieminen, Janne; Ruohtula, Terhi; Vaarala, Outi; Honkanen, Hanna; Hyöty, Heikki; Kondrashova, Anita; Oikarinen, Sami; Harmsen, Hermie J. M.; De Goffau, Marcus C.; Welling, Gjalt; Alahuhta, Kirsi; Virtanen, Suvi M.

    2015-01-01

    Upregulation of IL-17 immunity and detrimental effects of IL-17 on human islets have been implicated in human type 1 diabetes. In animal models, the plasticity of Th1/Th17 cells contributes to the development of autoimmune diabetes. In this study, we demonstrate that the upregulation of the IL-17 pathway and Th1/Th17 plasticity in peripheral blood are markers of advanced β cell autoimmunity and impaired β cell function in human type 1 diabetes. Activated Th17 immunity was observed in the late stage of preclinical diabetes in children with β cell autoimmunity and impaired glucose tolerance, but not in children with early β cell autoimmunity. We found an increased ratio of IFN-γ/IL-17 expression in Th17 cells in children with advanced β cell autoimmunity, which correlated with HbA1c and plasma glucose concentrations in an oral glucose tolerance test, and thus impaired β cell function. Low expression of Helios was seen in Th17 cells, suggesting that Th1/Th17 cells are not converted thymus-derived regulatory T cells. Our results suggest that the development of Th1/Th17 plasticity may serve as a biomarker of disease progression from β cell autoantibody positivity to type 1 diabetes. These data in human type 1 diabetes emphasize the role of Th1/Th17 plasticity as a potential contributor to tissue destruction in autoimmune conditions. PMID:25480564

  15. Automated regional behavioral analysis for human brain images

    National Research Council Canada - National Science Library

    Lancaster, Jack L; Laird, Angela R; Eickhoff, Simon B; Martinez, Michael J; Fox, P Mickle; Fox, Peter T

    2012-01-01

    Behavioral categories of functional imaging experiments along with standardized brain coordinates of associated activations were used to develop a method to automate regional behavioral analysis of human brain images...

  16. Simulating human behavior for understanding and managing environmental resource use

    NARCIS (Netherlands)

    Jager, Wander; Mosler, Hans Joachim

    2007-01-01

    Computer simulation allows for the experimental study of dynamic interactions between human behavior and complex environmental systems. Behavioral determinants and processes as identified in social-scientific theory may be formalized in simulated agents to obtain a better understanding of

  17. A discrete thermodynamic approach for modeling anisotropic coupled plasticity-damage behavior in geomaterials

    Science.gov (United States)

    Zhu, Qi-zhi; Shao, Jian-fu; Kondo, Djimedo

    2008-04-01

    In the present Note, we present a discrete thermodynamic approach for modeling coupled anisotropic plastic flow and damage evolution in geomaterials. The basic idea is to extend the widely-used isotropic coupled elastoplastic damage formulation to the case with induced anisotropy using a discrete approach. The total plastic strain is considered as the consequence of frictional sliding in weak sliding planes randomly distributed in the elastic solid matrix. The effective elastic tensor of damaged material is determined using damage variable associated with each family of weak sliding planes. An example of application is shown for a typical semi-brittle rock. To cite this article: Q.-Z. Zhu et al., C. R. Mecanique 336 (2008).

  18. Humans with Type-2 Diabetes Show Abnormal Long-Term Potentiation-Like Cortical Plasticity Associated with Verbal Learning Deficits

    Science.gov (United States)

    Fried, Peter J.; Schilberg, Lukas; Brem, Anna-Katharine; Saxena, Sadhvi; Wong, Bonnie; Cypess, Aaron M.; Horton, Edward S.; Pascual-Leone, Alvaro

    2016-01-01

    Background Type-2 diabetes mellitus (T2DM) accelerates cognitive aging and increases risk of Alzheimer’s disease. Rodent models of T2DM show altered synaptic plasticity associated with reduced learning and memory. Humans with T2DM also show cognitive deficits, including reduced learning and memory, but the relationship of these impairments to the efficacy of neuroplastic mechanisms has never been assessed. Objective Our primary objective was to compare mechanisms of cortical plasticity in humans with and without T2DM. Our secondary objective was to relate plasticity measures to standard measures of cognition. Methods A prospective cross-sectional cohort study was conducted on 21 adults with T2DM and 15 demographically-similar non-diabetic controls. Long-term potentiation-like plasticity was assessed in primary motor cortex by comparing the amplitude of motor evoked potentials (MEPs) from single-pulse transcranial magnetic stimulation before and after intermittent theta-burst stimulation (iTBS). Plasticity measures were compared between groups and related to neuropsychological scores. Results In T2DM, iTBS-induced modulation of MEPs was significantly less than controls, even after controlling for potential confounds. Furthermore, in T2DM, modulation of MEPs 10-min post-iTBS was significantly correlated with Rey Auditory Verbal Learning Task (RAVLT) performance. Conclusion Humans with T2DM show abnormal cortico-motor plasticity that is correlated with reduced verbal learning. Since iTBS after-effects and the RAVLT are both NMDA receptor-dependent measures, their relationship in T2DM may reflect brain-wide alterations in the efficacy of NMDA receptors. These findings offer novel mechanistic insights into the brain consequences of T2DM and provide a reliable means to monitor brain health and evaluate the efficacy of clinical interventions. PMID:27636847

  19. The role of human natural killer-1 (HNK-1) carbohydrate in neuronal plasticity and disease.

    Science.gov (United States)

    Morise, Jyoji; Takematsu, Hiromu; Oka, Shogo

    2017-10-01

    The human natural killer-1 (HNK-1) carbohydrate, a unique trisaccharide possessing sulfated glucuronic acid in a non-reducing terminus (HSO3-3GlcAß1-3Galß1-4GlcNAc-), is highly expressed in the nervous system and its spatiotemporal expression is strictly regulated. Mice deficient in the gene encoding a key enzyme, GlcAT-P, of the HNK-1 biosynthetic pathway exhibit almost complete disappearance of the HNK-1 epitope in the brain, significant reduction of long-term potentiation, and aberration of spatial learning and memory formation. In addition to its physiological roles in higher brain function, the HNK-1 carbohydrate has attracted considerable attention as an autoantigen associated with peripheral demyelinative neuropathy, which relates to IgM paraproteinemia, because of high immunogenicity. It has been suggested, however, that serum autoantibodies in IgM anti-myelin-associated glycoprotein (MAG) antibody-associated neuropathy patients show heterogeneous reactivity to the HNK-1 epitope. We have found that structurally distinct HNK-1 epitopes are expressed in specific proteins in the nervous system. Here, we overview the current knowledge of the involvement of these HNK-1 epitopes in the regulation of neural plasticity and discuss the impact of different HNK-1 antigens of anti-MAG neuropathy patients. We identified the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptor subunit GluA2 and aggrecan as HNK-1 carrier proteins. The HNK-1 epitope on GluA2 and aggrecan regulates neural plasticity in different ways. Furthermore, we found the clinical relationship between reactivity of autoantibodies to the different HNK-1 epitopes and progression of anti-MAG neuropathy. The HNK-1 epitope is indispensable for the acquisition of normal neuronal function and can be a good target for the establishment of diagnostic criteria for anti-MAG neuropathy. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. UV exposure modulates hemidesmosome plasticity, contributing to long-term pigmentation in human skin

    Science.gov (United States)

    Coelho, Sergio G.; Valencia, Julio C.; Yin, Lanlan; Smuda, Christoph; Mahns, Andre; Kolbe, Ludger; Miller, Sharon A.; Beer, Janusz Z.; Zhang, Guofeng; Tuma, Pamela L.; Hearing, Vincent J.

    2014-01-01

    Human skin color, i.e. pigmentation, differs widely among individuals as do their responses to various types of ultraviolet radiation (UV) and their risks of skin cancer. In some individuals UV-induced pigmentation persists for months to years in a phenomenon termed long-lasting pigmentation (LLP). It is unclear whether LLP is an indicator of potential risk for skin cancer. LLP seems to have similar features to other forms of hyperpigmentation, e.g. solar lentigines or age spots, which are clinical markers of photodamage and risk factors for precancerous lesions. To investigate what UV-induced molecular changes may persist in individuals with LLP, clinical specimens from non-sunburn-inducing repeated UV exposures (UVA, UVB or UVA+UVB) at 4 months post-exposure (short-term LLP) were evaluated by microarray analysis and dataset mining. Validated targets were further evaluated in clinical specimens from 6 healthy individuals (3 LLP+ and 3 LLP-) followed for more than 9 months (long-term LLP) who initially received a single sunburn-inducing UVA+UVB exposure. The results support a UV-induced hyperpigmentation model in which basal keratinocytes have an impaired ability to remove melanin that leads to a compensatory mechanism by neighboring keratinocytes with increased proliferative capacity to maintain skin homeostasis. The attenuated expression of SOX7 and other hemidesmosomal components (integrin α6β4 and plectin) leads to increased melanosome uptake by keratinocytes and points to a spatial regulation within the epidermis. The reduced density of hemidesmosomes provides supporting evidence for plasticity at the epidermal-dermal junction. Altered hemidesmosome plasticity, and the sustained nature of LLP, may be mediated by the role of SOX7 in basal keratinocytes. The long-term sustained subtle changes detected are modest, but sufficient to create dramatic visual differences in skin color. These results suggest that the hyperpigmentation phenomenon leading to increased

  1. Relationship between anelastic and non-linear visco-plastic behavior of 316 stainless steel at low homologous temperature

    Energy Technology Data Exchange (ETDEWEB)

    Nir, N.; Huang, F.H.; Hart, E.W.; Li, C.Y.

    1976-05-01

    At low homologous temperature the plastic strain rate seems to be controlled largely by dislocation glide friction. However, since a sizeable fraction of the applied stress sigma is dissipated in overcoming the strong barriers due to dislocation tangles generated by strain hardening, only a portion of the applied stress is actually expended against the frictional resistance. A recent model for this process includes the role of dislocation pile-ups at the strong barriers. The pile-ups provide a mechanism for producing the internal back stresses that limit the effective frictional stress. The also appear in the deformation as a stored anelastic strain component. The resultant behavior at low temperature and high stress is similar to that proposed by Grupta and Li. The same model also predicts an anelastic behavior at low stress. Measurements at both high and low stress levels on 316 Stainless Steel have now shown that the predictions of the model are quantitatively consistent at both stress levels.

  2. Thermal expansion behavior of co-extruded wood-plastic composites with glass-fiber reinforced shells

    Directory of Open Access Journals (Sweden)

    Runzhou Huang

    2012-11-01

    Full Text Available Coextruded wood-plastic composites (WPCs with glass-fiber (GF filled shells were manufactured, and their thermal expansion behavior was studied. A three-dimensional finite element model (FEM considering differential properties of both shell and core layers was developed to predict the linear coefficient of thermal expansion (LCTE of the material. It was shown that the LCTE values varied with composite structure and composition (i.e., core-shell thicknesses and materials. The use of GF-filled shells helped lower overall composite LCTE values. The imbalance of shell and core LCTE, and their moduli led to complex stress fields within a given composite system. The FEM predicted a trend of LCTE change with varying composite structures, which was in good agreement with the experimental data. This study provides for the first time a finite element modeling technique to optimize raw material composition and composite structure for optimizing thermal expansion behavior of co-extruded WPCs.

  3. Achieving large macroscopic compressive plastic deformation and work-hardening-like behavior in a monolithic bulk metallic glass by tailoring stress distribution

    Science.gov (United States)

    Chen, L. Y.; Ge, Q.; Qu, S.; Jiang, Q. K.; Nie, X. P.; Jiang, J. Z.

    2008-05-01

    The limited plastic deformation and lack of work hardening seriously restrict the applications of bulk metallic glasses (BMGs). Here, large macroscopic compressive plastic deformation (over 15%) and work-hardening-like behavior were achieved in a monolithic BMG through tailoring loading stress distribution experimentally. Numerical analysis was also carried out to investigate the stress distribution under the same mechanical condition. It is shown that loading induced stress gradient is responsible for the achievement mentioned above.

  4. The plasticity of human breast carcinoma cells is more than epithelial to mesenchymal conversion

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Ole William; Nielsen, Helga Lind; Gudjonsson, Thorarinn; Villadsen, Ren& #233; ; Ronnov-Jessen, Lone; Bissell, Mina J.

    2001-05-12

    The human breast comprises three lineages: the luminal epithelial lineage, the myoepithelial lineage, and the mesenchymal lineage. It has been widely accepted that human breast neoplasia pertains only to the luminal epithelial lineage. In recent years, however, evidence has accumulated that neoplastic breast epithelial cells may be substantially more plastic in their differentiation repertoire than previously anticipated. Thus, along with an increasing availability of markers for the myoepithelial lineage, at least a partial differentiation towards this lineage is being revealed frequently. It has also become clear that conversions towards the mesenchymal lineage actually occur, referred to as epithelial to mesenchymal transitions. Indeed, some of the so-called myofibroblasts surrounding the tumor may indeed have an epithelial origin rather than a mesenchymal origin. Because myoepithelial cells, epithelial to mesenchymal transition-derived cells, genuine stromal cells and myofibroblasts share common markers, we now need to define a more ambitious set of markers to distinguish these cell types in the microenvironment of the tumors. This is necessary because the different microenvironments may confer different clinical outcomes. The aim of this commentary is to describe some of the inherent complexities in defining cellular phenotypes in the microenvironment of breast cancer and to expand wherever possible on the implications for tumor suppression and progression.

  5. Occlusion of LTP-like plasticity in human primary motor cortex by action observation.

    Directory of Open Access Journals (Sweden)

    Jean-François Lepage

    Full Text Available Passive observation of motor actions induces cortical activity in the primary motor cortex (M1 of the onlooker, which could potentially contribute to motor learning. While recent studies report modulation of motor performance following action observation, the neurophysiological mechanism supporting these behavioral changes remains to be specifically defined. Here, we assessed whether the observation of a repetitive thumb movement--similarly to active motor practice--would inhibit subsequent long-term potentiation-like (LTP plasticity induced by paired-associative stimulation (PAS. Before undergoing PAS, participants were asked to either 1 perform abductions of the right thumb as fast as possible; 2 passively observe someone else perform thumb abductions; or 3 passively observe a moving dot mimicking thumb movements. Motor evoked potentials (MEP were used to assess cortical excitability before and after motor practice (or observation and at two time points following PAS. Results show that, similarly to participants in the motor practice group, individuals observing repeated motor actions showed marked inhibition of PAS-induced LTP, while the "moving dot" group displayed the expected increase in MEP amplitude, despite differences in baseline excitability. Interestingly, LTP occlusion in the action-observation group was present even if no increase in cortical excitability or movement speed was observed following observation. These results suggest that mere observation of repeated hand actions is sufficient to induce LTP, despite the absence of motor learning.

  6. Synaptic plasticity in a recurrent neural network for versatile and adaptive behaviors of a walking robot

    DEFF Research Database (Denmark)

    Grinke, Eduard; Tetzlaff, Christian; Wörgötter, Florentin

    2015-01-01

    mechanisms with plasticity, exteroceptive sensory feedback, and biomechanics. The neural mechanisms consist of adaptive neural sensory processing and modular neural locomotion control. The sensory processing is based on a small recurrent neural network consisting of two fully connected neurons. Online...... correlation-based learning with synaptic scaling is applied to adequately change the connections of the network. By doing so, we can effectively exploit neural dynamics (i.e., hysteresis effects and single attractors) in the network to generate different turning angles with short-term memory for a walking...

  7. Mechanical behavior of fiber/matrix interfaces in CFRP sheets subjected to plastic deformation

    Directory of Open Access Journals (Sweden)

    Kamiya Ryuta

    2016-01-01

    Full Text Available The use of Carbon Fiber Reinforced Plastic (CFRP is increasing markedly, partially in the aviation industry, but it has been considered that CFRP sheets cannot be formed by press-forming techniques owing to the low ductility of CFRP. Since the mechanical characteristics of CFRP are dominated by the microscale structure, it is possible to improve its formability by optimizing the material structure. Therefore, to improve the formability, the interaction between the carbon fibers and the matrix must be clarified. In this study, microscale analyses were conducted by a finite-element model with cohesive zone elements.

  8. Cerebellum to motor cortex paired associative stimulation induces bidirectional STDP-like plasticity in human motor cortex

    OpenAIRE

    Lu, Ming-Kuei; Tsai, Chon-Haw; Ziemann, Ulf

    2012-01-01

    The cerebellum is crucially important for motor control and adaptation. Recent non-invasive brain stimulation studies have indicated the possibility to alter the excitability of the cerebellum and its projections to the contralateral motor cortex, with behavioral consequences on motor control and adaptation. Here we sought to induce bidirectional spike-timing dependent plasticity (STDP)-like modifications of motor cortex (M1) excitability by application of paired associative stimulation (PAS)...

  9. PKA and ERK, but not PKC, in the amygdala contribute to pain-related synaptic plasticity and behavior

    Directory of Open Access Journals (Sweden)

    Ramsey Cara

    2008-07-01

    Full Text Available Abstract The laterocapsular division of the central nucleus of the amygdala (CeLC has emerged as an important site of pain-related plasticity and pain modulation. Glutamate and neuropeptide receptors in the CeLC contribute to synaptic and behavioral changes in the arthritis pain model, but the intracellular signaling pathways remain to be determined. This study addressed the role of PKA, PKC, and ERK in the CeLC. Adult male Sprague-Dawley rats were used in all experiments. Whole-cell patch-clamp recordings of CeLC neurons were made in brain slices from normal rats and from rats with a kaolin/carrageenan-induced monoarthritis in the knee (6 h postinduction. Membrane-permeable inhibitors of PKA (KT5720, 1 μM; cAMPS-Rp, 10 μM and ERK (U0126, 1 μM activation inhibited synaptic plasticity in slices from arthritic rats but had no effect on normal transmission in control slices. A PKC inhibitor (GF109203x, 1 μM and an inactive structural analogue of U0126 (U0124, 1 μM had no effect. The NMDA receptor-mediated synaptic component was inhibited by KT5720 or U0126; their combined application had additive effects. U0126 did not inhibit synaptic facilitation by forskolin-induced PKA-activation. Administration of KT5720 (100 μM, concentration in microdialysis probe or U0126 (100 μM into the CeLC, but not striatum (placement control, inhibited audible and ultrasonic vocalizations and spinal reflexes of arthritic rats but had no effect in normal animals. GF109203x (100 μM and U0124 (100 μM did not affect pain behavior. The data suggest that in the amygdala PKA and ERK, but not PKC, contribute to pain-related synaptic facilitation and behavior by increasing NMDA receptor function through independent signaling pathways.

  10. Reduction of endogenous kynurenic acid formation enhances extracellular glutamate, hippocampal plasticity, and cognitive behavior.

    Science.gov (United States)

    Potter, Michelle C; Elmer, Greg I; Bergeron, Richard; Albuquerque, Edson X; Guidetti, Paolo; Wu, Hui-Qiu; Schwarcz, Robert

    2010-07-01

    At endogenous brain concentrations, the astrocyte-derived metabolite kynurenic acid (KYNA) antagonizes the alpha 7 nicotinic acetylcholine receptor and, possibly, the glycine co-agonist site of the NMDA receptor. The functions of these two receptors, which are intimately involved in synaptic plasticity and cognitive processes, may, therefore, be enhanced by reductions in brain KYNA levels. This concept was tested in mice with a targeted deletion of kynurenine aminotransferase II (KAT II), a major biosynthetic enzyme of brain KYNA. At 21 days of age, KAT II knock-out mice had reduced hippocampal KYNA levels (-71%) and showed significantly increased performance in three cognitive paradigms that rely in part on the integrity of hippocampal function, namely object exploration and recognition, passive avoidance, and spatial discrimination. Moreover, compared with wild-type controls, hippocampal slices from KAT II-deficient mice showed a significant increase in the amplitude of long-term potentiation in vitro. These functional changes were accompanied by reduced extracellular KYNA (-66%) and increased extracellular glutamate (+51%) concentrations, measured by hippocampal microdialysis in vivo. Taken together, a picture emerges in which a reduction in the astrocytic formation of KYNA increases glutamatergic tone in the hippocampus and enhances cognitive abilities and synaptic plasticity. Our studies raise the prospect that interventions aimed specifically at reducing KYNA formation in the brain may constitute a promising molecular strategy for cognitive improvement in health and disease.

  11. Shielding behaviors of some polymer and plastic materials for gamma-rays

    Science.gov (United States)

    Mann, Kulwinder Singh; Rani, Asha; Heer, Manmohan Singh

    2015-01-01

    Gamma-rays interaction parameters with six polymer and plastic materials have been computed and investigated for their shielding behaviours in the experimental energy range 10-1400 keV. Low mass-density and ability to transform into thin-sheets of H-containing plastic and polymer materials generate the curiosity for present study. Gamma Ray Interaction Coefficients (GRIC)-toolkit: a computer program designed in MS-Excel, 2007 for the investigation. The toolkit has the capability to compute different parameters linked to shielding properties of the sample-material such that; mass attenuation coefficients (μ/ρ), mass energy absorption coefficients (μen/ρ), equivalent atomic number (Zeq), KERMA (kinetic energy released per unit mass). Polyvinyl Chloride (PVC) seems to be the best shield for gamma radiations in energy range 10-110 keV. The interaction parameters for selected samples have been computed and provided in the extended energy range 0.015-15 MeV.

  12. Influence of reaction parameters on brown coal-polyolefinic plastic co-pyrolysis behavior

    Energy Technology Data Exchange (ETDEWEB)

    Sharypov, V.I.; Beregovtsova, N.G.; Kuznetsov, B.N. [Institute of Chemistry and Chemical Technology SB RAS, K.Marx Str. 42, 660049 Krasnoyarsk (Russian Federation); Cebolla, V.L. [Instituto de Carboquimica, CSIC, Miguel Luesma, 4, 50015 Zaragoza (Spain); Collura, S.; Finqueneisel, G.; Zimny, T.; Weber, J.V. [Laboratoire de Chimie et Applications, Universite de Metz, rue V.Demange, 57500 Saint-Avold (France)

    2007-03-15

    Co-processing of polyolefinic polymers with Kansk-Achinsk (Russia) brown coal was investigated by thermogravimetry (TG) and autoclave pyrolysis under argon and hydrogen pressure in catalytic conditions (or not). Gas chromatography-mass spectrometry (GC-MS) and high performance thin layer chromatography (HPTLC) were used to analyze the distillate products. Some synergistic effects indicate chemical interaction between the products of thermal decomposition of coal and plastic. In co-pyrolysis under H{sub 2} a significant increasing of coal conversion degree as a function of polymer amount in feedstock was found. Simultaneously the coal promoted formation of distillate products from polymers. Some alkyl aromatic and O-containing substances were detected in co-pyrolysis fraction boiling in the range 180-350 C, indicating interactions between coal and plastic. Iron containing ore materials, modified by mechanochemical treatment, demonstrated a catalytic activity in hydropyrolysis process. In catalytic conditions, increases of the mixtures conversion degree by 9-13 wt.%, of distillate fraction yields by 1.2-1.6 times and a decrease of olefins and polycyclic components were observed. (author)

  13. Effects of diazepam and levodopa single doses on motor cortex plasticity modulation in healthy human subjects: A TMS study

    Directory of Open Access Journals (Sweden)

    Ilić Nela V.

    2012-01-01

    Full Text Available Introduction. Administration of pharmacological agents with specific actions on neurotransmitter systems is a powerful driver of functional cortical reorganization. Plastic reorganization of the motor cortex in humans studies by the use of non-invasive stimulation protocols, which mimic the Hebbian model of associative plasticity. Objective. Aiming to explore pharmacological modulation on human motor cortex plasticity, we tested healthy subjects after each dosage of diazepam, levodopa i placebo administration, using paired associative stimulation protocol (PAS that induce fenomena similar to a long-term potentiation and depression, as defined on the synaptic level. Methods. We analyzed effects of benzodiazepines (10 mg, levodopa (200 mg and placebo on PAS protocol in 14 healthy volunteers, using a double-blind placebo-controlled study design. PAS consisted of electrical stimuli pairs at n.medianus and magnetic pulses over the scalp (transcranial magnetic stimulation in precisely defined intervals (ISI was 10 and 25 ms for a total of about 15 minutes (200 pairs. MEP amplitudes before and after (0, 10, 20 and 30 minutes later interventional protocols were compared. Results. When protocols were applied with placebo depending on ISI (10 ms - inhibitory, 25 ms - facilitatory effects, MEP amplitudes decreased or increased, while values in the postinterventional period (0, 10, 20 and 30 min were compared with initial values before the use of SAS. The use of benzodiazepines caused the occlusion of LTP-like effect, in contrast to amplification effects recorded after the administration of levodopa. With respect to the LTD-like protocol, the reverse was true (ANOVA for repeat measurements p<0.001. Conclusion. Administration of GABA-ergic agonist diazepam interferes with the induction of associative plasticity in the motor cortex of healthy individuals, as opposed to the use of levodopa, which stimulates these processes. The observed effects point at a

  14. Plasticity of Corticospinal Neural Control after Locomotor Training in Human Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Maria Knikou

    2012-01-01

    Full Text Available Spinal lesions substantially impair ambulation, occur generally in young and otherwise healthy individuals, and result in devastating effects on quality of life. Restoration of locomotion after damage to the spinal cord is challenging because axons of the damaged neurons do not regenerate spontaneously. Body-weight-supported treadmill training (BWSTT is a therapeutic approach in which a person with a spinal cord injury (SCI steps on a motorized treadmill while some body weight is removed through an upper body harness. BWSTT improves temporal gait parameters, muscle activation patterns, and clinical outcome measures in persons with SCI. These changes are likely the result of reorganization that occurs simultaneously in supraspinal and spinal cord neural circuits. This paper will focus on the cortical control of human locomotion and motor output, spinal reflex circuits, and spinal interneuronal circuits and how corticospinal control is reorganized after locomotor training in people with SCI. Based on neurophysiological studies, it is apparent that corticospinal plasticity is involved in restoration of locomotion after training. However, the neural mechanisms underlying restoration of lost voluntary motor function are not well understood and translational neuroscience research is needed so patient-orientated rehabilitation protocols to be developed.

  15. Group 3 innate lymphoid cells (ILC3s): Origin, differentiation, and plasticity in humans and mice.

    Science.gov (United States)

    Montaldo, Elisa; Juelke, Kerstin; Romagnani, Chiara

    2015-08-01

    Since their discovery, innate lymphoid cells (ILCs) have been the subject of intense research. As their name implies, ILCs are innate cells of lymphoid origin, and can be grouped into subsets based on their cytotoxic activity, cytokine profile, and the transcriptional requirements during ILC differentiation. The main ILC groups are "killer" ILCs, comprising NK cells, and "helper-like" ILCs (including ILC1s, ILC2s, and ILC3s). This review examines the origin, differentiation stages, and plasticity of murine and human ILC3s. ILC3s express the retinoic acid receptor (RAR) related orphan receptor RORγt and the signature cytokines IL-22 and IL-17. Fetal ILC3s or lymphoid tissue inducer cells are required for lymphoid organogenesis, while postnatally developing ILC3s are important for the generation of intestinal cryptopatches and isolated lymphoid follicles as well as for the defence against pathogens and epithelial homeostasis. Here, we discuss the transcription factors and exogenous signals (including cytokines, nutrients and cell-to-cell interaction) that drive ILC3 lineage commitment and acquisition of their distinctive effector program.

  16. Functional plasticity before the cradle: a review of neural functional imaging in the human fetus.

    Science.gov (United States)

    Anderson, Amy L; Thomason, Moriah E

    2013-11-01

    The organization of the brain is highly plastic in fetal life. Establishment of healthy neural functional systems during the fetal period is essential to normal growth and development. Across the last several decades, remarkable progress has been made in understanding the development of human fetal functional brain systems. This is largely due to advances in imaging methodologies. Fetal neuroimaging began in the 1950-1970's with fetal electroencephalography (EEG) applied during labor. Later, in the 1980's, magnetoencephalography (MEG) emerged as an effective approach for investigating fetal brain function. Most recently, functional magnetic resonance imaging (fMRI) has arisen as an additional powerful approach for examining fetal brain function. This review will discuss major developmental findings from fetal imaging studies such as the maturation of prenatal sensory system functions, functional hemispheric asymmetry, and sensory-driven neurodevelopment. We describe how with improved imaging and analysis techniques, functional imaging of the fetus has the potential to assess the earliest point of neural maturation and provide insight into the patterning and sequence of normal and abnormal brain development. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Task decomposition: a framework for comparing diverse training models in human brain plasticity studies

    Directory of Open Access Journals (Sweden)

    Emily B. J. Coffey

    2013-10-01

    Full Text Available Training studies, in which the structural or functional neurophysiology is compared before and after expertise is acquired, are increasingly being used as models for understanding the human brain’s potential for reorganization. It is proving difficult to use these results to answer basic and important questions like how task training leads to both specific and general changes in behaviour and how these changes correspond with modifications in the brain. The main culprit is the diversity of paradigms used as complex task models. An assortment of activities ranging from juggling to deciphering Morse code has been reported. Even when working in the same general domain, few researchers use similar training models. New ways to meaningfully compare complex tasks are needed. We propose a method for characterizing and deconstructing the task requirements of complex training paradigms, which is suitable for application to both structural and functional neuroimaging studies. We believe this approach will aid brain plasticity research by making it easier to compare training paradigms, identify ‘missing puzzle pieces’, and encourage researchers to design training protocols to bridge these gaps.

  18. Evidence for high-fidelity timing-dependent synaptic plasticity of human motor cortex.

    Science.gov (United States)

    Cash, R F H; Mastaglia, F L; Thickbroom, G W

    2013-01-01

    A single transcranial magnetic stimulation (TMS) pulse typically evokes a short series of spikes in corticospinal neurons [known as indirect (I)-waves] which are thought to arise from transynaptic input. Delivering a second pulse at inter-pulse intervals (IPIs) corresponding to the timing of these I-waves leads to a facilitation of the response, and if stimulus pairs are delivered repeatedly, a persistent LTP-like increase in excitability can occur. This has been demonstrated at an IPI of 1.5 ms, which corresponds to the first I-wave interval, in an intervention referred to as ITMS (I-wave TMS), and it has been argued that this may have similarities with timing-dependent plasticity models. Consequently, we hypothesized that if the second stimulus is delivered so as not to coincide with I-wave timing, it should lead to LTD. We performed a crossover study in 10 subjects in which TMS doublets were timed to coincide (1.5-ms IPI, ITMS(1.5)) or not coincide (2-ms IPI, ITMS(2)) with I-wave firing. Single pulse motor-evoked potential (MEP) amplitude, resting motor threshold (RMT), and short-interval cortical inhibition (SICI) were measured from the first dorsal interosseous (FDI) muscle. After ITMS(1.5) corticomotor excitability was increased by ~60% for 15 min (P < 0.05) and returned to baseline by 20 min. Increasing the IPI by just 500 μs to 2 ms reversed the aftereffect, and MEP amplitude was significantly reduced (~35%, P < 0.05) for 15 min before returning to baseline. This reduction was not associated with an increase in SICI, suggesting a reduction in excitatory transmission rather than an increase in inhibitory efficacy. RMT also remained unchanged, suggesting that these changes were not due to changes in membrane excitability. Amplitude-matching ITMS(2) did not modulate excitability. The results are consistent with timing-dependent synaptic LTP/D-like effects and suggest that there are plasticity mechanisms operating in the human motor cortex with a temporal

  19. Flex Fatigue Behavior Of Plastic Optical Fibers With Low Bending Cycles

    Directory of Open Access Journals (Sweden)

    Huang Juan

    2015-06-01

    Full Text Available Flex fatigue behaviour of plastic optical fibres (POFs with the diameters of 0.2 and 0.3 mm under different pretensions is measured with fatigue life curve by flexometer. The fatigue sensitivity coefficient is calculated by the linear fitting curve of normalised stress versus logarithm of bending cycles. The residual modulus is investigated during the flex fatigue processes. The results exhibit the exponential relationship between applied pretension and numbers of bending cycles at break. It is indicated that the flex fatigue of POFs might be sensitive with high swing angle or swing speed. There is an evident loss of modulus for two POFs with pretensions of 4 and 10% of ultimate tensile strength during 10-times bending cycles. The values of residual modulus of two POFs almost keep constant after 10-times bending cycles.

  20. The AAA+ ATPase, Thorase Regulates AMPA Receptor-Dependent Synaptic Plasticity and Behavior

    Science.gov (United States)

    Zhang, Jianmin; Wang, Yue; Chi, Zhikai; Keuss, Matthew J.; Pai, Ying-Min Emily; Kang, Ho Chul; Shin, Jooho; Bugayenko, Artem; Wang, Hong; Xiong, Yulan; Pletnikov, Mikhail V.; Mattson, Mark P.; Dawson, Ted M.; Dawson, Valina L.

    2011-01-01

    SUMMARY The synaptic insertion or removal of AMPA receptors (AMPAR) plays critical roles in the regulation of synaptic activity reflected in the expression of long-term potentiation (LTP) and long-term depression (LTD). The cellular events underlying this important process in learning and memory are still being revealed. Here we describe and characterize the AAA+ ATPase, Thorase, that regulates the expression of surface AMPAR. In an ATPase-dependent manner Thorase mediates the internalization of AMPAR by disassembling the AMPAR-GRIP1 complex. Following genetic deletion of Thorase, the internalization of AMPAR is substantially reduced, leading to increased amplitudes of miniature excitatory postsynaptic currents, enhancement of LTP and elimination of LTD. These molecular events are expressed as deficits in learning and memory in Thorase null mice. This study identifies an AAA+ ATPase that plays a critical role in regulating the surface expression of AMPAR and thereby regulates synaptic plasticity and learning and memory. PMID:21496646

  1. Non-Hertzian behavior in binary collisions of plastic balls derived from impact acoustics.

    Science.gov (United States)

    Riner, Joshua; Petculescu, Andi

    2010-07-01

    This paper presents slight deviations from Hertz's impact law, inferred from acoustic signatures of polypropylene ball collisions. An impact acoustics model is used to fit the acoustic data. The model is built upon a generalized relationship between impact force (F) and deformation (xi) of the form F=kappaxi(alpha). Agreement with experiment is reached when alpha and kappa differ from Hertz's values by -6.25% and +1%, respectively. The difference is ascribable to non-idealities such as slight material inhomogeneities, impact-point asymmetry, plasticity etc. Also, the collision energy released as sound, which is usually dismissed as negligible, is derived from data fitting. The acoustic-to-incident energy ratio, dependent on impact duration, is constrained to be on the order of 100 ppm.

  2. Learning and retrieval behavior in recurrent neural networks with pre-synaptic dependent homeostatic plasticity

    Science.gov (United States)

    Mizusaki, Beatriz E. P.; Agnes, Everton J.; Erichsen, Rubem; Brunnet, Leonardo G.

    2017-08-01

    The plastic character of brain synapses is considered to be one of the foundations for the formation of memories. There are numerous kinds of such phenomenon currently described in the literature, but their role in the development of information pathways in neural networks with recurrent architectures is still not completely clear. In this paper we study the role of an activity-based process, called pre-synaptic dependent homeostatic scaling, in the organization of networks that yield precise-timed spiking patterns. It encodes spatio-temporal information in the synaptic weights as it associates a learned input with a specific response. We introduce a correlation measure to evaluate the precision of the spiking patterns and explore the effects of different inhibitory interactions and learning parameters. We find that large learning periods are important in order to improve the network learning capacity and discuss this ability in the presence of distinct inhibitory currents.

  3. Fatigue Hardening Behavior of 1.5 GPa Grade Transformation-Induced Plasticity-Aided Martensitic Steel

    Science.gov (United States)

    Sugimoto, Koh-Ichi; Hojo, Tomohiko

    2016-11-01

    Low cycle fatigue hardening/softening behavior of a 0.2 pct C-1.5 pct Si-1.5 pct Mn-1.0 pct Cr-0.2 pct Mo-0.05 pct Nb transformation-induced plasticity (TRIP)-aided steel consisting of a wide lath martensite structure matrix and a narrow lath martensite-metastable retained austenite mixture was investigated. The steel exhibited notable fatigue hardening in the same way as TRIP-aided bainitic ferrite steel, although conventional martensitic steel such as SCM420 steel with the same tensile strength exhibited fatigue softening. The considerable fatigue hardening of this steel is believed to be associated mainly with the compressive internal stress that results from a difference in flow stress between the matrix and the martensite-austenite-like phase, with a small contribution from the strain-induced transformation and dislocation hardenings.

  4. Effects of Severe Plastic Deformation and Heat Treatment on Transformation Behavior of Explosively Welded Duplex TiNi-TiNi

    Institute of Scientific and Technical Information of China (English)

    Li Juntao; Zheng Yanjun; Cui Lishan

    2007-01-01

    The effects of severe plastic deformation and heat treatment on the transformation behavior of explosively welded duplex TiNi-TiNi shape memory alloys (SMAs) were investigated by differential scanning calorimeter (DSC) measurements. The explosively welded duplex TiNi-TiNi plate of 0.7 mm thickness was cold-rolled at room temperature to a 60% reduction in thickness and then annealed at different temperatures for different durations. The results showed that low temperature (623-723K) heat-treatment led to the crystallization of the amorphous region, and re-crystallization occurred in the specimens annealed at higher temperatures (over 873 K). Research indicated that the change of martensitic transformation temperature is due to the change of internal stresses with increasing heat treatment temperature. The change of annealing time also led to a change in martensitic transformation temperature, which was associated with the precipitation and decomposition of Ti3Ni4 in TiNi-1.

  5. Indentation Pileup Behavior of Ti-6Al-4V Alloy: Experiments and Nonlocal Crystal Plasticity Finite Element Simulations

    Science.gov (United States)

    Han, Fengbo; Tang, Bin; Yan, Xu; Peng, Yifei; Kou, Hongchao; Li, Jinshan; Deng, Ying; Feng, Yong

    2017-01-01

    This study reports on the indentation pileup behavior of Ti-6Al-4V alloy. Berkovich nanoindentation was performed on a specimen with equiaxed microstructure. The indented area was characterized by electron backscattered diffraction (EBSD) to obtain the indented grain orientations. Surface topographies of several indents were measured by atomic force microscopy (AFM). The pileup patterns on the indented surfaces show significant orientation dependence. Corresponding nonlocal crystal plasticity finite element (CPFE) simulations were carried out to predict the pileup patterns. Analysis of the cumulative shear strain distributions and evolutions for different slip systems around the indents found that the pileups are mainly caused by prismatic slip. The pileup patterns evolve with the loading and unloading process, and the change in pileup height due to the elastic recovery at unloading stage is significant. The density distributions of geometrically necessary dislocations (GNDs) around the indent were predicted. Simulation of nanoindentation on a tricrystal model was performed.

  6. Indentation Pileup Behavior of Ti-6Al-4V Alloy: Experiments and Nonlocal Crystal Plasticity Finite Element Simulations

    Science.gov (United States)

    Han, Fengbo; Tang, Bin; Yan, Xu; Peng, Yifei; Kou, Hongchao; Li, Jinshan; Deng, Ying; Feng, Yong

    2017-04-01

    This study reports on the indentation pileup behavior of Ti-6Al-4V alloy. Berkovich nanoindentation was performed on a specimen with equiaxed microstructure. The indented area was characterized by electron backscattered diffraction (EBSD) to obtain the indented grain orientations. Surface topographies of several indents were measured by atomic force microscopy (AFM). The pileup patterns on the indented surfaces show significant orientation dependence. Corresponding nonlocal crystal plasticity finite element (CPFE) simulations were carried out to predict the pileup patterns. Analysis of the cumulative shear strain distributions and evolutions for different slip systems around the indents found that the pileups are mainly caused by prismatic slip. The pileup patterns evolve with the loading and unloading process, and the change in pileup height due to the elastic recovery at unloading stage is significant. The density distributions of geometrically necessary dislocations (GNDs) around the indent were predicted. Simulation of nanoindentation on a tricrystal model was performed.

  7. The Difference of Structural State and Deformation Behavior between Teenage and Mature Human Dentin.

    Science.gov (United States)

    Panfilov, Peter; Zaytsev, Dmitry; Antonova, Olga V; Alpatova, Victoria; Kiselnikova, Larissa P

    2016-01-01

    Objective. The cause of considerable elasticity and plasticity of human dentin is discussed in the relationship with its microstructure. Methods. Structural state of teenage and mature human dentin is examined by using XRD and TEM techniques, and their deformation behavior under compression is studied as well. Result. XRD study has shown that crystallographic type of calcium hydroxyapatite in human dentin (calcium hydrogen phosphate hydroxide Ca9HPO4(PO4)5OH; Space Group P63/m (176); a = 9,441 A; c = 6,881 A; c/a = 0,729; Crystallite (Scherrer) 200 A) is the same for these age groups. In both cases, dentin matrix is X-ray amorphous. According to TEM examination, there are amorphous and ultrafine grain phases in teenage and mature dentin. Mature dentin is stronger on about 20% than teenage dentin, while teenage dentin is more elastic on about 20% but is less plastic on about 15% than mature dentin. Conclusion. The amorphous phase is dominant in teenage dentin, whereas the ultrafine grain phase becomes dominant in mature dentin. Mechanical properties of human dentin under compression depend on its structural state, too.

  8. The Difference of Structural State and Deformation Behavior between Teenage and Mature Human Dentin

    Directory of Open Access Journals (Sweden)

    Peter Panfilov

    2016-01-01

    Full Text Available Objective. The cause of considerable elasticity and plasticity of human dentin is discussed in the relationship with its microstructure. Methods. Structural state of teenage and mature human dentin is examined by using XRD and TEM techniques, and their deformation behavior under compression is studied as well. Result. XRD study has shown that crystallographic type of calcium hydroxyapatite in human dentin (calcium hydrogen phosphate hydroxide Ca9HPO4(PO45OH; Space Group P63/m (176; a = 9,441 A; c = 6,881 A; c/a = 0,729; Crystallite (Scherrer 200 A is the same for these age groups. In both cases, dentin matrix is X-ray amorphous. According to TEM examination, there are amorphous and ultrafine grain phases in teenage and mature dentin. Mature dentin is stronger on about 20% than teenage dentin, while teenage dentin is more elastic on about 20% but is less plastic on about 15% than mature dentin. Conclusion. The amorphous phase is dominant in teenage dentin, whereas the ultrafine grain phase becomes dominant in mature dentin. Mechanical properties of human dentin under compression depend on its structural state, too.

  9. Transcranial magnetic stimulation provides means to assess cortical plasticity and excitability in humans with fragile X syndrome and autism spectrum disorder

    Directory of Open Access Journals (Sweden)

    Lindsay M Oberman

    2010-06-01

    Full Text Available Fragile X Syndrome (FXS is the most common heritable cause of intellectual disability. In vitro electrophysiologic data from mouse models of FXS suggest that loss of Fragile X Mental Retardation Protein (FMRP affects intracortical excitability and synaptic plasticity. Specifically, the cortex appears hyperexcitable, and use-dependent long-term potentiation (LTP and long-term depression (LTD of synaptic strength are abnormal. Though animal models provide important information, FXS and other neurodevelopmental disorders are human diseases and as such translational research to evaluate cortical excitability and plasticity must be applied in the human. Transcranial magnetic stimulation (TMS paradigms have recently been developed to noninvasively investigate cortical excitability using paired-pulse stimulation, as well as LTP- and LTD-like synaptic plasticity in response to theta burst stimulation (TBS in vivo in the human. TBS applied on consecutive days can be used to measure metaplasticity (the ability of the synapse to undergo a second plastic change following a recent induction of plasticity. The current study investigated intracortical inhibition, plasticity and metaplasticity in full mutation females with FXS, participants with autism spectrum disorders (ASD, and neurotypical controls. Results suggest that intracortical inhibition is normal in participants with FXS, while plasticity and metaplasticity appear abnormal. ASD participants showed abnormalities in plasticity and metaplasticity, as well as heterogeneity in intracortical inhibition. Our findings highlight the utility of noninvasive neurophysiological measures to translate insights from animal models to humans with neurodevelopmental disorders, and thus provide direct confirmation of cortical dysfunction in patients with FXS and ASD.

  10. Postnatal lead exposure and the cholinergic system: effects on cholinergically mediated behaviors and cholinergic development and plasticity in the hippocampus

    Energy Technology Data Exchange (ETDEWEB)

    Alfano, D.P.

    1982-01-01

    A review of previous evidence suggested the possibility of a functional association between the behavioral effect of early lead (Pb) exposure, hippocampal damage and cholinergic deficiency. To further assess this possibility, Long-Evans hooded rat pups were exposed to Pb for the first 25 postnatal days via the maternal milk. Beginning at 65 days of age, animals were tested on behavioral tasks sensitive to both Pb exposure and cholinergic deficiency. Exposure to both levels of Pb impaired passive avoidance acquisition and produced lower rates of spontaneous alternation. The anticholinergic scopolamine (0.4 mg/kg) impaired passive avoidance acquisition, lowered the rate of spontaneous alternation and decreased open field activity scores in control animals. At 30 days of age, the brains of High Pb and control animals were processed for acetylcholinesterase (AChE) histochemistry. Morphometric evaluation of the molecular layer of the hippocampal dentate gyrus indicated no effects of Pb on the development of the cholinergic innervation of this brain region. The results provide strong evidence for the involvement of deficient cholinergic functioning in the behavioral changes observed following postnatal Pb exposure. Further, these findings indicate that a decrease in neuroanatomical plasticity may be a critical brain mechanism underlying the learning deficits observed following exposure to Pb.

  11. Time course of the induction of homeostatic plasticity generated by repeated transcranial direct current stimulation of the human motor cortex.

    Science.gov (United States)

    Fricke, K; Seeber, A A; Thirugnanasambandam, N; Paulus, W; Nitsche, M A; Rothwell, J C

    2011-03-01

    Several mechanisms have been proposed that control the amount of plasticity in neuronal circuits and guarantee dynamic stability of neuronal networks. Homeostatic plasticity suggests that the ease with which a synaptic connection is facilitated/suppressed depends on the previous amount of network activity. We describe how such homeostatic-like interactions depend on the time interval between two conditioning protocols and on the duration of the preconditioning protocol. We used transcranial direct current stimulation (tDCS) to produce short-lasting plasticity in the motor cortex of healthy humans. In the main experiment, we compared the aftereffect of a single 5-min session of anodal or cathodal tDCS with the effect of a 5-min tDCS session preceded by an identical 5-min conditioning session administered 30, 3, or 0 min beforehand. Five-minute anodal tDCS increases excitability for about 5 min. The same duration of cathodal tDCS reduces excitability. Increasing the duration of tDCS to 10 min prolongs the duration of the effects. If two 5-min periods of tDCS are applied with a 30-min break between them, the effect of the second period of tDCS is identical to that of 5-min stimulation alone. If the break is only 3 min, then the second session has the opposite effect to 5-min tDCS given alone. Control experiments show that these shifts in the direction of plasticity evolve during the 10 min after the first tDCS session and depend on the duration of the first tDCS but not on intracortical inhibition and facilitation. The results are compatible with a time-dependent "homeostatic-like" rule governing the response of the human motor cortex to plasticity probing protocols.

  12. The adaptive functions of sexual plasticity: the suppression and surreptitious expression of human sociosexuality.

    Science.gov (United States)

    Josephs, Lawrence

    2012-06-01

    Tendencies toward non-monogamy and bisexual expression may constitute primate-wide predispositions that have been conserved in humans. This observation is supported by studies of sexual development and behavior in our primate relatives and sexually permissive premodern tribal cultures including hunter-gatherers. Nevertheless, even in sexually permissive societies, there may be considerable sexual possessiveness and jealousy as well as attempts at parental control of children's marital choices. This is associated with punitive revenge against unfaithful spouses and mate poaching rivals and parent/offspring conflict around marital choices. There is no paradise lost despite the greater sexual freedom. Humans may be adaptively designed to suppress each other's sexuality due to sexual jealousy and parental desires to control children's sexuality but also to surreptitiously evade those restrictions, though there is considerable cross-cultural variability in the level of sexual restrictiveness.

  13. Operant behavior to obtain palatable food modifies neuronal plasticity in the brain reward circuit.

    Science.gov (United States)

    Guegan, Thomas; Cutando, Laura; Ayuso, Eduard; Santini, Emanuela; Fisone, Gilberto; Bosch, Fatima; Martinez, Albert; Valjent, Emmanuel; Maldonado, Rafael; Martin, Miquel

    2013-02-01

    Palatability enhances food intake by hedonic mechanisms that prevail over caloric necessities. Different studies have demonstrated the role of endogenous cannabinoids in the mesocorticolimbic system in controlling food hedonic value and consumption. We hypothesize that the endogenous cannabinoid system could also be involved in the development of food-induced behavioral alterations, such as food-seeking and binge-eating, by a mechanism that requires neuroplastic changes in the brain reward pathway. For this purpose, we evaluated the role of the CB1 cannabinoid receptor (CB1-R) in the behavioral and neuroplastic changes induced by operant training for standard, highly caloric or highly palatable isocaloric food using different genetics, viral and pharmacological approaches. Neuroplasticity was evaluated by measuring changes in dendritic spine density in neurons previously labeled with the dye DiI. Only operant training to obtain highly palatable isocaloric food induced neuroplastic changes in neurons of the nucleus accumbens shell and prefrontal cortex that were associated to changes in food-seeking behavior. These behavioral and neuroplastic modifications induced by highly palatable isocaloric food were dependent on the activity of the CB1-R. Neuroplastic changes induced by highly palatable isocaloric food are similar to those produced by some drugs of abuse and may be crucial in the alteration of food-seeking behavior leading to overweight and obesity.

  14. Human Behavioral Contributions to Climate Change: Psychological and Contextual Drivers

    Science.gov (United States)

    Swim, Janet K.; Clayton, Susan; Howard, George S.

    2011-01-01

    We are facing rapid changes in the global climate, and these changes are attributable to human behavior. Humans produce this global impact through our use of natural resources, multiplied by the vast increase in population seen in the past 50 to 100 years. Our goal in this article is to examine the underlying psychosocial causes of human impact,…

  15. Effect of cholesterol and triglycerides levels on the rheological behavior of human blood

    Science.gov (United States)

    Moreno, Leonardo; Calderas, Fausto; Sanchez-Olivares, Guadalupe; Medina-Torres, Luis; Sanchez-Solis, Antonio; Manero, Octavio

    2015-02-01

    Important public health problems worldwide such as obesity, diabetes, hyperlipidemia and coronary diseases are quite common. These problems arise from numerous factors, such as hyper-caloric diets, sedentary habits and other epigenetic factors. With respect to Mexico, the population reference values of total cholesterol in plasma are around 200 mg/dL. However, a large proportion has higher levels than this reference value. In this work, we analyze the rheological properties of human blood obtained from 20 donors, as a function of cholesterol and triglyceride levels, upon a protocol previously approved by the health authorities. Samples with high and low cholesterol and triglyceride levels were selected and analyzed by simple-continuous and linear-oscillatory shear flow. Rheometric properties were measured and related to the structure and composition of human blood. In addition, rheometric data were modeled by using several constitutive equations: Bautista-Manero-Puig (BMP) and the multimodal Maxwell equations to predict the flow behavior of human blood. Finally, a comparison was made among various models, namely, the BMP, Carreau and Quemada equations for simple shear rate flow. An important relationship was found between cholesterol, triglycerides and the structure of human blood. Results show that blood with high cholesterol levels (400 mg/dL) has flow properties fully different (higher viscosity and a more pseudo-plastic behavior) than blood with lower levels of cholesterol (tendency to Newtonian behavior or viscosity plateau at low shear rates).

  16. Middle Egypt in prehistory: A search for the origins of modern human behavior and human dispersal

    OpenAIRE

    Olszewski, D.; McPherron, S.; Dibble, H.; Soressi, M.

    2001-01-01

    Focuses on the evolution of human behavior and dispersal in Egypt. Examination on the genetic relationship of groups of people living in the area; Importance of the study of stone artifacts the explain the origins of human behavior; Assumption on the routes taken by humans to disperse in the area.

  17. Flow behavior and plasticity of Ti-6Al-4V under different electrically assisted treatments

    Science.gov (United States)

    Jiang, Tianhao; Peng, Linfa; Yi, Peiyun; Lai, Xinmin

    2016-12-01

    Both electrically assisted tension (EAT) and electrically assisted pre-treatment tension (EAPT) were conducted to compare different effects on improving deformation resistance and ductility of Ti-6Al-4V. It is found EAPT obviously enhanced the ductility of Ti-6Al-4V compared with that obtained in EAT. In order to decouple the thermal effect from electro-plastic effect, thermally assisted tension (TAT) as well as thermally assisted pre-treatment tension (TAPT) were also conducted. The result indicates deformation mechanism of alpha phase with h.c.p crystal structure in Ti-6Al-4V was insensitive to electric current when current duty is less than 20%. However, the elevated temperature alone is insufficient to account for additional stress drop in the initial yielding stress observed in EAT and EAPT when current duty is higher than 20%. According to XRD investigation on specimens treated in original state, TAPT and EAPT, it is found electric current accelerates the annihilation of alpha phase and formation of beta phase in Ti-6Al-4V more effectively than the rising temperature does and such microstructure evolution also throws light on the improvement of flow stress and ductility observed in EAPT both experimentally and theoretically.

  18. Multisensory integration and behavioral plasticity in sharks from different ecological niches.

    Directory of Open Access Journals (Sweden)

    Jayne M Gardiner

    Full Text Available The underwater sensory world and the sensory systems of aquatic animals have become better understood in recent decades, but typically have been studied one sense at a time. A comprehensive analysis of multisensory interactions during complex behavioral tasks has remained a subject of discussion without experimental evidence. We set out to generate a general model of multisensory information extraction by aquatic animals. For our model we chose to analyze the hierarchical, integrative, and sometimes alternate use of various sensory systems during the feeding sequence in three species of sharks that differ in sensory anatomy and behavioral ecology. By blocking senses in different combinations, we show that when some of their normal sensory cues were unavailable, sharks were often still capable of successfully detecting, tracking and capturing prey by switching to alternate sensory modalities. While there were significant species differences, odor was generally the first signal detected, leading to upstream swimming and wake tracking. Closer to the prey, as more sensory cues became available, the preferred sensory modalities varied among species, with vision, hydrodynamic imaging, electroreception, and touch being important for orienting to, striking at, and capturing the prey. Experimental deprivation of senses showed how sharks exploit the many signals that comprise their sensory world, each sense coming into play as they provide more accurate information during the behavioral sequence of hunting. The results may be applicable to aquatic hunting in general and, with appropriate modification, to other types of animal behavior.

  19. Multisensory integration and behavioral plasticity in sharks from different ecological niches.

    Science.gov (United States)

    Gardiner, Jayne M; Atema, Jelle; Hueter, Robert E; Motta, Philip J

    2014-01-01

    The underwater sensory world and the sensory systems of aquatic animals have become better understood in recent decades, but typically have been studied one sense at a time. A comprehensive analysis of multisensory interactions during complex behavioral tasks has remained a subject of discussion without experimental evidence. We set out to generate a general model of multisensory information extraction by aquatic animals. For our model we chose to analyze the hierarchical, integrative, and sometimes alternate use of various sensory systems during the feeding sequence in three species of sharks that differ in sensory anatomy and behavioral ecology. By blocking senses in different combinations, we show that when some of their normal sensory cues were unavailable, sharks were often still capable of successfully detecting, tracking and capturing prey by switching to alternate sensory modalities. While there were significant species differences, odor was generally the first signal detected, leading to upstream swimming and wake tracking. Closer to the prey, as more sensory cues became available, the preferred sensory modalities varied among species, with vision, hydrodynamic imaging, electroreception, and touch being important for orienting to, striking at, and capturing the prey. Experimental deprivation of senses showed how sharks exploit the many signals that comprise their sensory world, each sense coming into play as they provide more accurate information during the behavioral sequence of hunting. The results may be applicable to aquatic hunting in general and, with appropriate modification, to other types of animal behavior.

  20. Plastic Surgery

    Science.gov (United States)

    ... Surgery? A Week of Healthy Breakfasts Shyness Plastic Surgery KidsHealth > For Teens > Plastic Surgery Print A A ... forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word "plastic" ...

  1. Modeling and simulating human teamwork behaviors using intelligent agents

    Science.gov (United States)

    Fan, Xiaocong; Yen, John

    2004-12-01

    Among researchers in multi-agent systems there has been growing interest in using intelligent agents to model and simulate human teamwork behaviors. Teamwork modeling is important for training humans in gaining collaborative skills, for supporting humans in making critical decisions by proactively gathering, fusing, and sharing information, and for building coherent teams with both humans and agents working effectively on intelligence-intensive problems. Teamwork modeling is also challenging because the research has spanned diverse disciplines from business management to cognitive science, human discourse, and distributed artificial intelligence. This article presents an extensive, but not exhaustive, list of work in the field, where the taxonomy is organized along two main dimensions: team social structure and social behaviors. Along the dimension of social structure, we consider agent-only teams and mixed human-agent teams. Along the dimension of social behaviors, we consider collaborative behaviors, communicative behaviors, helping behaviors, and the underpinning of effective teamwork-shared mental models. The contribution of this article is that it presents an organizational framework for analyzing a variety of teamwork simulation systems and for further studying simulated teamwork behaviors.

  2. Evidence from neuroimaging to explore brain plasticity in humans during an ultra-endurance burden

    Directory of Open Access Journals (Sweden)

    Perrey Stéphane

    2012-12-01

    Full Text Available Abstract Physical activity, likely through induction of neuroplasticity, is a promising intervention to promote brain health. In athletes it is clear that training can and does, by physiological adaptations, extend the frontiers of performance capacity. The limits of our endurance capacity lie deeply in the human brain, determined by various personal factors yet to be explored. The human brain, with its vast neural connections and its potential for seemingly endless behaviors, constitutes one of the final frontiers of medicine. In a recent study published in BMC Medicine, the TransEurope FootRace Project followed 10 ultra-endurance runners over around 4,500 km across Europe and recorded a large data collection of brain imaging scans. This study indicates that the cerebral atrophy amounting to a reduction of approximately 6% throughout the two months of the race is reversed upon follow-up. While this study will contribute to advances in the limits of human performance on the neurophysiological processes in sports scientists, it will also bring important understanding to clinicians about cerebral atrophy in people who are vulnerable to physical and psychological stress long term. See related research article http://www.biomedcentral.com/1741-7015/10/170

  3. Three-Dimensional Crystal Plasticity Finite Element Simulation of Hot Compressive Deformation Behaviors of 7075 Al Alloy

    Science.gov (United States)

    Li, Lei-Ting; Lin, Y. C.; Li, Ling; Shen, Lu-Ming; Wen, Dong-Xu

    2015-03-01

    Three-dimensional crystal plasticity finite element (CPFE) method is used to investigate the hot compressive deformation behaviors of 7075 aluminum alloy. Based on the grain morphology and crystallographic texture of 7075 aluminum alloy, the microstructure-based representative volume element (RVE) model was established by the pole figure inversion approach. In order to study the macroscopic stress-strain response and microstructural evolution, the CPFE simulations are performed on the established microstructure-based RVE model. It is found that the simulated stress-strain curves and deformation texture well agree with the measured results of 7075 aluminum alloy. With the increasing deformation degree, the remained initial weak Goss texture component tends to be strong and stable, which may result in the steady flow stress. The grain orientation and grain misorientation have significant effects on the deformation heterogeneity during hot compressive deformation. In the rolling-normal plane, the continuity of strain and misorientation can maintain across the low-angle grain boundaries, while the discontinuity of strain and misorientation is observed at the high-angle grain boundaries. The simulated results demonstrate that the developed CPFE model can well describe the hot compressive deformation behaviors of 7075 aluminum alloy under elevated temperatures.

  4. State-dependent and timing-dependent bidirectional associative plasticity in the human SMA-M1 network.

    Science.gov (United States)

    Arai, Noritoshi; Müller-Dahlhaus, Florian; Murakami, Takenobu; Bliem, Barbara; Lu, Ming-Kuei; Ugawa, Yoshikazu; Ziemann, Ulf

    2011-10-26

    The supplementary motor area (SMA-proper) plays a key role in the preparation and execution of voluntary movements. Anatomically, SMA-proper is densely reciprocally connected to primary motor cortex (M1), but neuronal coordination within the SMA-M1 network and its modification by external perturbation are not well understood. Here we modulated the SMA-M1 network using MR-navigated multicoil associative transcranial magnetic stimulation in healthy subjects. Changes in corticospinal excitability were assessed by recording motor evoked potential (MEP) amplitude bilaterally in a hand muscle. We found timing-dependent bidirectional Hebbian-like MEP changes during and for at least 30 min after paired associative SMA-M1 stimulation. MEP amplitude increased if SMA stimulation preceded M1 stimulation by 6 ms, but decreased if SMA stimulation lagged M1 stimulation by 15 ms. This associative plasticity in the SMA-M1 network was highly topographically specific because paired associative stimulation of pre-SMA and M1 did not result in any significant MEP change. Furthermore, associative plasticity in the SMA-M1 network was strongly state-dependent because it required priming by near-simultaneous M1 stimulation to occur. We conclude that timing-dependent bidirectional associative plasticity is demonstrated for the first time at the systems level of a human corticocortical neuronal network. The properties of this form of plasticity are fully compatible with spike-timing-dependent plasticity as defined at the cellular level. The necessity of priming may reflect the strong interhemispheric connectivity of the SMA-M1 network. Findings are relevant for better understanding reorganization and potentially therapeutic modification of neuronal coordination in the SMA-M1 network after cerebral lesions such as stroke.

  5. Dynamic behavior of oscillatory plastic flow in a smectic liquid crystal

    Science.gov (United States)

    Herke, Richard A.; Clark, 1., Noel A.; Handschy, Mark A.

    1997-09-01

    Dynamic surface force measurements are used to study the response of a smectic-A liquid crystal under layer-normal stress. The smectic A is confined in a spherical wedge between crossed cylindrical surfaces having a minimum gap spacing of 0.5-4 μm. The force transmitted between the surfaces by the liquid crystal is measured vs surface spacing using a capacitance micrometer-based surface force apparatus. Above a threshold stress plastic flow results, consisting of individual layers being excluded or included. Each layer flow event has an intriguing dynamical structure, beginning with an enhanced drift rate, which can last for many minutes, accelerating to a rapid separation change of ~1 or 2 s duration wherein the bulk of the relaxation occurs, and tapering off to a background drift rate over a period of a 100 s or more. The single-layer nature of the observed jumps in liquid crystal thickness indicates that they are topological in origin, i.e., slippage events in the phase of the smectic-A order parameter that must necessarily involve edge or screw dislocations. A model based on the Glaberson-Clem-Oswald-Kléman helical instability in screw dislocations is the only one found to explain the data, the layering events arising from a cascade of these helical instabilities sweeping radially outward through the smectic-A sample. The slow precursor acceleration is due to the nucleation of a few helices in the thin central portion of the sample. As time goes on, the force relieved is transferred to the rest of the sample, pushing larger and larger amounts of the area into the unstable regime, and a type of chain reaction occurs whereby the bulk of a layer is removed. In the end only the material at the edge of the droplet, where the thickness is largest, is left to slowly continue to nucleate, producing a long-term tail.

  6. Kansei Behavior of Robots Following Instruction of Human

    Directory of Open Access Journals (Sweden)

    Satoru Shibata

    2015-10-01

    Full Text Available When coexisting with humans and support them, robots need to be instructed to move by humans without burden, and the motion should not to instigate anxiety but to be accepted to human psychology. To realize Kansei behavior of robots following instruction of human, the concept of “Kansei transfer function”, which can add softness and smoothness to robots, is explained, and the effectiveness of its applications to humanrobot interfaces is confirmed from psychological aspects.

  7. Obesogenic diet intake during pregnancy programs aberrant synaptic plasticity and addiction-like behavior to a palatable food in offspring.

    Science.gov (United States)

    Camacho, Alberto; Montalvo-Martinez, Larisa; Cardenas-Perez, Robbi E; Fuentes-Mera, Lizeth; Garza-Ocañas, Lourdes

    2017-07-14

    Contextual food conditioned behaviors require plasticity of glutamatergic neurotransmission in the reward system, involving changes in the expression of including a-amino-3-hydroxy-5-methylisoxazole 4-propionate receptors (AMPA), N-methyl-d-aspartic acid (NMDA) and metabotropic glutamate 2,3 (mGlur 2,3). However, the role of changes in glutamatergic synaptic markers on energy-dense palatable food preference during development has not been described. Here, we determine the effect of nutritional programing during gestation on fat food choices using a conditioned place preference (CPP) test and an operant training response and its effect on glutamatergic markers in the nucleus accumbens (Nac) shell and prefrontal cortex (PFC). Our data showed that rats displayed preference for palatable fat food and an increase in caloric intake when compared to a chow diet. Notably, 74% of rats showing a preference for fat food intake correlate with a positive HFD-paired score whereas 26% failed to get HFD-conditioned. Also, male rats trained under an operant training response schedule (FR1, FR5 and PR) showed high and low responder groups to work for food. Notably, hypercaloric nutritional programing of female rats leads to exacerbation for reinforcers in female offspring compared to offspring from chow diet. Finally, we found that an operant training response to palatable reinforcers correlates with upregulation of mGlur 2,3 in the NAc shell and PFC of male rats and female offspring. Also, we found selective Nr1 upregulation in NAc shell and the PFC of female offspring. Our data suggest that nutritional programing by hypercaloric intake leads to incentive motivation to work for food and synaptic plasticity alteration in the mesolimbic system. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Application of plasticity theory to soil behavior : a new sand model

    OpenAIRE

    1983-01-01

    The representation of rheological soil behavior by constitutive equations is a now branch of soil mechanics which has been expanding for 30 years. Based on continuum mechanics, numerical methods (finite elements) and experimental techniques, this now discipline allows practicing engineers to solve complex geotechnical problems. Although all soils are constituted of discrete mineral particles, forces and displacements within them are represented by continuous stresses and strains. Most stress-...

  9. Behavioral and neural plasticity caused by early social experiences: the case of the honeybee

    Directory of Open Access Journals (Sweden)

    Andrés eArenas

    2013-08-01

    Full Text Available Cognitive experiences during the early stages of life play an important role in shaping future behavior. Behavioral and neural long-term changes after early sensory and associative experiences have been recently reported in the honeybee. This invertebrate is an excellent model for assessing the role of precocious experiences on later behavior due to its extraordinarily tuned division of labor based on age polyethism. These studies are mainly focused on the role and importance of experiences occurred during the first days of the adult lifespan, their impact on foraging decisions and their contribution to coordinate food gathering. Odor-rewarded experiences during the first days of honeybee adulthood alter the responsiveness to sucrose, making young hive bees more sensitive to assess gustatory features about the nectar brought back to the hive and affecting the dynamic of the food transfers and the propagation of food-related information within the colony as well. Early olfactory experiences lead to stable and long-term associative memories that can be successfully recalled after many days, even at foraging ages. Also they improve memorizing of new associative learning events later in life. The establishment of early memories promotes stable reorganization of the olfactory circuits inducing structural and functional changes in the antennal lobe. Early rewarded experiences have relevant consequences at the social level too, biasing dance and trophallaxis partner choice and affecting recruitment. Here, we revised recent results in bees´ physiology, behavior and sociobiology to depict how the early experiences affect their cognition abilities and neural-related circuits.

  10. Operant behavior to obtain palatable food modifies neuronal plasticity in the brain reward circuit

    OpenAIRE

    Guegan, Thomas, 1983-; Cutando, Laura; Ayuso, Eduard; Santini, Emanuela; Fisone, Gilberto; Bosch, Fatima; Martínez, Albert; Valjent, Emmanuel; Maldonado, Rafael; Martín Sánchez, Miquel, 1971-

    2013-01-01

    Palatability enhances food intake by hedonic mechanisms that prevail over caloric necessities. Different studies have demonstrated the role of endogenous cannabinoids in the mesocorticolimbic system in controlling food hedonic value and consumption. We hypothesize that the endogenous cannabinoid system could also be involved in the development of food-induced behavioral alterations, such as food-seeking and binge-eating, by a mechanism that requires neuroplastic changes in the brain reward pa...

  11. Modeling for the Dynamics of Human Innovative Behaviors

    CERN Document Server

    Lin, Ying-Ting; Wang, Bing-Hong

    2013-01-01

    How to promote the innovative activities is an important problem for modern society. In this paper, combining with the evolutionary games and information spreading, we propose a lattice model to investigate dynamics of human innovative behaviors based on benefit-driven assumption. Simulations show several properties in agreement with peoples' daily cognition on innovative behaviors, such as slow diffusion of innovative behaviors, gathering of innovative strategy on "innovative centers", and quasi-localized dynamics. Furthermore, our model also emerges rich non-Poisson properties in the temporal-spacial patterns of the innovative status, including the scaling law in the interval time of innovation releases and the bimodal distributions on the spreading range of innovations, which would be universal in human innovative behaviors. Our model provide a basic framework on the study of the issue relevant to the evolution of human innovative behaviors and the promotion measurement of innovative activities.

  12. Detection of Unusual Human Activities Based on Behavior Modeling

    OpenAIRE

    Hiraishi, Kunihiko; Kobayashi, Koichi

    2014-01-01

    A type of services that require human physical actions and intelligent decision making exists in various real fields, such as nursing in hospitals and caregiving in nursing homes. In this paper, we propose new formalism for modeling human behavior in such services. Behavior models are estimated from event-logs, and can be used for analysis of human activities. We show two analysis methods: one is to detect unusual human activities that appear in event-logs, and the other is to find staffs tha...

  13. Behavioral Signal Processing: Deriving Human Behavioral Informatics From Speech and Language

    Science.gov (United States)

    Narayanan, Shrikanth; Georgiou, Panayiotis G.

    2013-01-01

    The expression and experience of human behavior are complex and multimodal and characterized by individual and contextual heterogeneity and variability. Speech and spoken language communication cues offer an important means for measuring and modeling human behavior. Observational research and practice across a variety of domains from commerce to healthcare rely on speech- and language-based informatics for crucial assessment and diagnostic information and for planning and tracking response to an intervention. In this paper, we describe some of the opportunities as well as emerging methodologies and applications of human behavioral signal processing (BSP) technology and algorithms for quantitatively understanding and modeling typical, atypical, and distressed human behavior with a specific focus on speech- and language-based communicative, affective, and social behavior. We describe the three important BSP components of acquiring behavioral data in an ecologically valid manner across laboratory to real-world settings, extracting and analyzing behavioral cues from measured data, and developing models offering predictive and decision-making support. We highlight both the foundational speech and language processing building blocks as well as the novel processing and modeling opportunities. Using examples drawn from specific real-world applications ranging from literacy assessment and autism diagnostics to psychotherapy for addiction and marital well being, we illustrate behavioral informatics applications of these signal processing techniques that contribute to quantifying higher level, often subjectively described, human behavior in a domain-sensitive fashion. PMID:24039277

  14. Low plastic ingestion rate in Atlantic cod (Gadus morhua) from Newfoundland destined for human consumption collected through citizen science methods.

    Science.gov (United States)

    Liboiron, Max; Liboiron, France; Wells, Emily; Richárd, Natalie; Zahara, Alexander; Mather, Charles; Bradshaw, Hillary; Murichi, Judyannet

    2016-12-15

    Marine microplastics are a contaminant of concern because their small size allows ingestion by a wide range of marine life. Using citizen science during the Newfoundland recreational cod fishery, we sampled 205 Atlantic cod (Gadus morhua) destined for human consumption and found that 5 had eaten plastic, an ingestion prevalence rate of 2.4%. This ingestion rate for Atlantic cod is the second lowest recorded rate in the reviewed published literature (the lowest is 1.4%), and the lowest for any fish in the North Atlantic. This is the first report for plastic ingestion in fish in Newfoundland, Canada, a province dependent on fish for sustenance and livelihoods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Neural Plasticity following Abacus Training in Humans: A Review and Future Directions

    Directory of Open Access Journals (Sweden)

    Yongxin Li

    2016-01-01

    Full Text Available The human brain has an enormous capacity to adapt to a broad variety of environmental demands. Previous studies in the field of abacus training have shown that this training can induce specific changes in the brain. However, the neural mechanism underlying these changes remains elusive. Here, we reviewed the behavioral and imaging findings of comparisons between abacus experts and average control subjects and focused on changes in activation patterns and changes in brain structure. Finally, we noted the limitations and the future directions of this field. We concluded that although current studies have provided us with information about the mechanisms of abacus training, more research on abacus training is needed to understand its neural impact.

  16. Neural Plasticity following Abacus Training in Humans: A Review and Future Directions.

    Science.gov (United States)

    Li, Yongxin; Chen, Feiyan; Huang, Wenhua

    2016-01-01

    The human brain has an enormous capacity to adapt to a broad variety of environmental demands. Previous studies in the field of abacus training have shown that this training can induce specific changes in the brain. However, the neural mechanism underlying these changes remains elusive. Here, we reviewed the behavioral and imaging findings of comparisons between abacus experts and average control subjects and focused on changes in activation patterns and changes in brain structure. Finally, we noted the limitations and the future directions of this field. We concluded that although current studies have provided us with information about the mechanisms of abacus training, more research on abacus training is needed to understand its neural impact.

  17. Informal Institutions and the "Weaknesses" of Human Behavior

    Science.gov (United States)

    2005-01-01

    Volkswirtschaftslehre ’ i LDepartment of Economics Discussion Paper No. January 2005 34 Informal Institutions and the "Weaknesses" of Human Behavior Markus G6bel...Diskussionspapiere der Faichergruppe Volkswirtschaftslehre "* Grbel, Markus & Tobias Thomas, Informal Institutions and the "Weaknesses" of Human Behavior, No... Volkswirtschaftslehre "* Braiuninger, Michael, Social Capital and Regional Mobility, Nr. 4/2002. "* Schdfer, Wolf, EU-Erweiterung: Anmerkungen zum Balassa

  18. Simulating human behavior for understanding and managing environmental resource use

    NARCIS (Netherlands)

    Jager, Wander; Mosler, Hans Joachim

    2007-01-01

    Computer simulation allows for the experimental study of dynamic interactions between human behavior and complex environmental systems. Behavioral determinants and processes as identified in social-scientific theory may be formalized in simulated agents to obtain a better understanding of man-enviro

  19. Facing History and Ourselves: Holocaust and Human Behavior.

    Science.gov (United States)

    Strom, Margot Stern; Parsons, William S.

    This unit for junior and senior high school students presents techniques and materials for studying about the holocaust of World War II. Emphasis in the guide is on human behavior and the role of the individual within society. Among the guide's 18 objectives are for students to examine society's influence on individual behavior, place Hitler's…

  20. Plastic fish

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness.   Artwork by Wolfgang Trettnak. Packaging materials, consumer goods (shoes, kids’ toys, etc.), leftovers from fishing and aquaculture activities… our oceans and beaches are full of plastic litter. Most of the debris from beaches is plastic bottles. “PET bottles have high durability and stability,” explains Wolfgang Trettnak, a chemist by education and artist from Austria, who gave a lecture on this topic organised by the Staff Association at CERN on 26 May. “PET degrades very slowly and the estimated lifetime of a bottle is 450 years.” In addition to the beach litter accumulated from human use, rivers bring several ki...

  1. Effect of Nanoclay on the Flexural Creep Behavior of Wood/Plastic Composites

    Science.gov (United States)

    Kord, B.; Sheykholeslami, A.; Najafi, A.

    2016-01-01

    The effect of nanoclay on the short-term flexural creep behavior of polypropylene/wood flour composites was investigated. The results obtained showed that the flexural strength and modulus increased with contentt of nanoclay up to 3 phc and then decreased. The fractional deflection and relative creep decreased with increasing content of nanoclay. X-ray diffraction patterns and transmission electron microscopy revealed that the nanocomposites formed were intercalated. Morphological findings testified that the samples containing 3 phc of nanoclay had the highest degree of intercalation and dispersion.

  2. The Histone H3K27 Demethylase UTX Regulates Synaptic Plasticity and Cognitive Behaviors in Mice

    Directory of Open Access Journals (Sweden)

    Gang-Bin Tang

    2017-08-01

    Full Text Available Histone demethylase UTX mediates removal of repressive trimethylation of histone H3 lysine 27 (H3K27me3 to establish a mechanistic switch to activate large sets of genes. Mutation of Utx has recently been shown to be associated with Kabuki syndrome, a rare congenital anomaly syndrome with dementia. However, its biological function in the brain is largely unknown. Here, we observe that deletion of Utx results in increased anxiety-like behaviors and impaired spatial learning and memory in mice. Loss of Utx in the hippocampus leads to reduced long-term potentiation and amplitude of miniature excitatory postsynaptic current, aberrant dendrite development and defective synapse formation. Transcriptional profiling reveals that Utx regulates a subset of genes that are involved in the regulation of dendritic morphology, synaptic transmission, and cognition. Specifically, Utx deletion disrupts expression of neurotransmitter 5-hydroxytryptamine receptor 5B (Htr5b. Restoration of Htr5b expression in newborn hippocampal neurons rescues the defects of neuronal morphology by Utx ablation. Therefore, we provide evidence that Utx plays a critical role in modulating synaptic transmission and cognitive behaviors. Utx cKO mouse models like ours provide a valuable means to study the underlying mechanisms of the etiology of Kabuki syndrome.

  3. Exercise but not (-)-epigallocatechin-3-gallate or β-alanine enhances physical fitness, brain plasticity, and behavioral performance in mice.

    Science.gov (United States)

    Bhattacharya, Tushar K; Pence, Brandt D; Ossyra, Jessica M; Gibbons, Trisha E; Perez, Samuel; McCusker, Robert H; Kelley, Keith W; Johnson, Rodney W; Woods, Jeffrey A; Rhodes, Justin S

    2015-06-01

    Nutrition and physical exercise can enhance cognitive function but the specific combinations of dietary bioactives that maximize pro-cognitive effects are not known nor are the contributing neurobiological mechanisms. Epigallocatechin-3-gallate (EGCG) is a flavonoid constituent of many plants with high levels found in green tea. EGCG has anti-inflammatory and anti-oxidant properties and is known to cross the blood brain barrier where it can affect brain chemistry and physiology. β-Alanine (B-ALA) is a naturally occurring β-amino acid that could increase cognitive functioning by increasing levels of exercise via increased capacity of skeletal muscle, by crossing the blood brain barrier and acting as a neurotransmitter, or by free radical scavenging in muscle and brain after conversion into carnosine. The objective of this study was to determine the effects of EGCG (~250mg/kg/day), B-ALA (~550mg/kg/day), and their combination with voluntary wheel running exercise on the following outcome measures: body composition, time to fatigue, production of new cells in the granule layer of the dentate gyrus of the hippocampus as a marker for neuronal plasticity, and behavioral performance on the contextual and cued fear conditioning tasks, as measures of associative learning and memory. Young adult male BALB/cJ mice approximately 2months old were randomized into 8 groups varying the nutritional supplement in their diet and access to running wheels over a 39day study period. Running increased food intake, decreased fat mass, increased time to exhaustive fatigue, increased numbers of new cells in the granule layer of the hippocampus, and enhanced retrieval of both contextual and cued fear memories. The diets had no effect on their own or in combination with exercise on any of the fitness, plasticity, and behavioral outcome measures other than B-ALA decreased percent body fat whereas EGCG increased lean body mass slightly. Results suggest that, in young adult BALB/cJ mice, a 39

  4. Exercise but not (-)-Epigallocatechin-3-gallate or β-Alanine enhances physical fitness, brain plasticity, and behavioral performance in mice

    Science.gov (United States)

    Bhattacharya, Tushar K.; Pence, Brandt D.; Ossyra, Jessica M.; Gibbons, Trisha E.; Perez, Samuel; McCusker, Robert H.; Kelley, Keith W.; Johnson, Rodney W.; Woods, Jeffrey A.; Rhodes, Justin S.

    2015-01-01

    Nutrition and physical exercise can enhance cognitive function but the specific combinations of dietary bioactives that maximize pro-cognitive effects are not known nor are the contributing neurobiological mechanisms. Epigallocatechin-3-gallate (EGCG) is a flavonoid constituent of many plants with high levels found in green tea. EGCG has anti-inflammatory and anti-oxidant properties and is known to cross the blood brain barrier where it can affect brain chemistry and physiology. β-alanine (B-ALA) is a naturally occurring β–amino acid that could increase cognitive functioning by increasing levels of exercise via increased capacity of skeletal muscle, by crossing the blood brain barrier and acting as a neurotransmitter, or by free radical scavenging in muscle and brain after conversion into carnosine. The objective of this study was to determine the effects of EGCG (∼ 250 mg/kg/day), B-ALA (∼550 mg/kg/day), and their combination with voluntary wheel running exercise on the following outcome measures: body composition, time to fatigue, production of new cells in the granule layer of the dentate gyrus of the hippocampus as a marker for neuronal plasticity, and behavioral performance on the contextual and cued fear conditioning tasks, as measures of associative learning and memory. Young adult male BALB/cJ mice approximately 2 months old were randomized into 8 groups varying the nutritional supplement in their diet and access to running wheels over a 39 day study period. Running increased food intake, decreased fat mass, increased time to exhaustive fatigue, increased numbers of new cells in the granule layer of the hippocampus, and enhanced retrieval of both contextual and cued fear memories. The diets had no effect on their own or in combination with exercise on any of the fitness, plasticity, and behavioral outcome measures other than B-ALA decreased percent body fat whereas EGCG increased lean body mass slightly. Results suggest that, in young adult BALB

  5. Viscoelastic behavior of discrete human collagen fibrils

    DEFF Research Database (Denmark)

    2010-01-01

    on the strain. The slope of the viscous response showed a strain rate dependence corresponding to a power function of powers 0.242 and 0.168 for the two patellar tendon fibrils, respectively. In conclusion, the present work provides direct evidence of viscoelastic behavior at the single fibril level, which has...

  6. Anomalous human behavior detection: An Adaptive approach

    NARCIS (Netherlands)

    Leeuwen, C. van; Halma, A.; Schutte, K.

    2013-01-01

    Detection of anomalies (outliers or abnormal instances) is an important element in a range of applications such as fault, fraud, suspicious behavior detection and knowledge discovery. In this article we propose a new method for anomaly detection and performed tested its ability to detect anomalous

  7. Behavior genetic modeling of human fertility

    DEFF Research Database (Denmark)

    Rodgers, J L; Kohler, H P; Kyvik, K O;

    2001-01-01

    Try) and number of children (NumCh). Behavior genetic models were fitted using structural equation modeling and DF analysis. A consistent medium-level additive genetic influence was found for NumCh, equal across genders; a stronger genetic influence was identified for FirstTry, greater for females than for males...

  8. Anomalous human behavior detection: An Adaptive approach

    NARCIS (Netherlands)

    Leeuwen, C. van; Halma, A.; Schutte, K.

    2013-01-01

    Detection of anomalies (outliers or abnormal instances) is an important element in a range of applications such as fault, fraud, suspicious behavior detection and knowledge discovery. In this article we propose a new method for anomaly detection and performed tested its ability to detect anomalous b

  9. Oxytocin receptor genetic variation promotes human trust behavior

    Directory of Open Access Journals (Sweden)

    Frank eKrueger

    2012-02-01

    Full Text Available Given that human trust behavior is heritable and intranasal administration of oxytocin enhances trust, the oxytocin receptor (OXTR gene is an excellent candidate to investigate genetic contributions to individual variations in trust behavior. Although a single-nucleotide polymorphism involving an adenine (A/ guanine (G transition (rs53576 has been associated with socio-emotional phenotypes, its link to trust behavior is unclear. We combined genotyping of healthy male students with the administration of a trust game experiment. Our results show that a naturally occurring genetic variation (rs53576 in the OXTR gene is reliably associated with trust behavior rather than a general increase in trustworthy or risk behaviors. Individuals homozygous for the G allele (GG showed higher trust behavior than individuals with A allele carriers (AA/AG. Although the molecular functionality of this polymorphism is still unknown, future research should clarify how the OXTR gene interacts with other genes and the environment in promoting socio-emotional behaviors.

  10. Novel technology of electroless Ni-W-P on plastics and its interface behavior

    Institute of Scientific and Technical Information of China (English)

    WANG Tian-xu; HU Yong-jun; MENG Ji-long

    2004-01-01

    The electroless Ni-W-P coatings on polyoxymethylene(POM) were prepared. The POM was pretreated by hot spraying Al powder on it. Before the electroless Ni-W-P deposition, the POM with Al coating was flash plated in alkaline bath. The mechanism of Ni-W-P deposition was studied and the technology was optimized. The XRD analysis shows that the "as-deposited" Ni-W-P plating has mixed crystalline structure. The hardness value of deposits is more than HV700. The abrasion resistance of deposits is six times more than that of POM. Bending test was used to determine the cohesion between the deposits and the substrates. SEM was used to study the behavior of surface abrasion and interface bonding condition. The reason for the excellent cohesion was interpreted.

  11. Transcranial magnetic stimulation and motor plasticity in human lateral cerebellum : Dual effect on saccadic adaptation

    NARCIS (Netherlands)

    Panouilleres, Muriel; Neggers, Sebastiaan F. W.; Gutteling, Tjerk P.; Salemme, Romeo; van der Stigchel, Stefan; van der Geest, Josef N.; Frens, Maarten A.; Pelisson, Denis

    2012-01-01

    The cerebellum is a key area for movement control and sensory-motor plasticity. Its medial part is considered as the exclusive cerebellar center controlling the accuracy and adaptive calibration of saccadic eye movements. However, the contribution of other zones situated in its lateral part is unkno

  12. Plasticity of the human visual system after retinal gene therapy in patients with Leber’s congenital amaurosis

    Science.gov (United States)

    Ashtari, Manzar; Zhang, Hui; Cook, Philip A.; Cyckowski, Laura L.; Shindler, Kenneth S.; Marshall, Kathleen A.; Aravand, Puya; Vossough, Arastoo; Gee, James C.; Maguire, Albert M.; Baker, Chris I.; Bennett, Jean

    2015-01-01

    Much of our knowledge of the mechanisms underlying plasticity in the visual cortex in response to visual impairment, vision restoration, and environmental interactions comes from animal studies. We evaluated human brain plasticity in a group of patients with Leber’s congenital amaurosis (LCA), who regained vision through gene therapy. Using non-invasive multimodal neuroimaging methods, we demonstrated that reversing blindness with gene therapy promoted long-term structural plasticity in the visual pathways emanating from the treated retina of LCA patients. The data revealed improvements and normalization along the visual fibers corresponding to the site of retinal injection of the gene therapy vector carrying the therapeutic gene in the treated eye compared to the visual pathway for the untreated eye of LCA patients. After gene therapy, the primary visual pathways (for example, geniculostriate fibers) in the treated retina were similar to those of sighted control subjects, whereas the primary visual pathways of the untreated retina continued to deteriorate. Our results suggest that visual experience, enhanced by gene therapy, may be responsible for the reorganization and maturation of synaptic connectivity in the visual pathways of the treated eye in LCA patients. The interactions between the eye and the brain enabled improved and sustained long-term visual function in patients with LCA after gene therapy. PMID:26180100

  13. Cerebellum to motor cortex paired associative stimulation induces bidirectional STDP-like plasticity in human motor cortex.

    Science.gov (United States)

    Lu, Ming-Kuei; Tsai, Chon-Haw; Ziemann, Ulf

    2012-01-01

    The cerebellum is crucially important for motor control and adaptation. Recent non-invasive brain stimulation studies have indicated the possibility to alter the excitability of the cerebellum and its projections to the contralateral motor cortex, with behavioral consequences on motor control and adaptation. Here we sought to induce bidirectional spike-timing dependent plasticity (STDP)-like modifications of motor cortex (M1) excitability by application of paired associative stimulation (PAS) in healthy subjects. Conditioning stimulation over the right lateral cerebellum (CB) preceded focal transcranial magnetic stimulation (TMS) of the left M1 hand area at an interstimulus interval of 2 ms (CB→M1 PAS(2 ms)), 6 ms (CB→M1 PAS(6 ms)) or 10 ms (CB→M1 PAS(10 ms)) or randomly alternating intervals of 2 and 10 ms (CB→M1 PAS(Control)). Effects of PAS on M1 excitability were assessed by the motor-evoked potential (MEP) amplitude, short-interval intracortical inhibition (SICI), intracortical facilitation (ICF) and cerebellar-motor cortex inhibition (CBI) in the first dorsal interosseous muscle of the right hand. CB→M1 PAS(2 ms) resulted in MEP potentiation, CB→M1 PAS(6 ms) and CB→M1 PAS(10 ms) in MEP depression, and CB→M1 PAS(Control) in no change. The MEP changes lasted for 30-60 min after PAS. SICI and CBI decreased non-specifically after all PAS protocols, while ICF remained unaltered. The physiological mechanisms underlying these MEP changes are carefully discussed. Findings support the notion of bidirectional STDP-like plasticity in M1 mediated by associative stimulation of the cerebello-dentato-thalamo-cortical pathway and M1. Future studies may investigate the behavioral significance of this plasticity.

  14. A Culture-Behavior-Brain Loop Model of Human Development.

    Science.gov (United States)

    Han, Shihui; Ma, Yina

    2015-11-01

    Increasing evidence suggests that cultural influences on brain activity are associated with multiple cognitive and affective processes. These findings prompt an integrative framework to account for dynamic interactions between culture, behavior, and the brain. We put forward a culture-behavior-brain (CBB) loop model of human development that proposes that culture shapes the brain by contextualizing behavior, and the brain fits and modifies culture via behavioral influences. Genes provide a fundamental basis for, and interact with, the CBB loop at both individual and population levels. The CBB loop model advances our understanding of the dynamic relationships between culture, behavior, and the brain, which are crucial for human phylogeny and ontogeny. Future brain changes due to cultural influences are discussed based on the CBB loop model.

  15. The multifactorial nature of human homosexual behavior: A brief review

    Directory of Open Access Journals (Sweden)

    Barona, Daniel

    2014-12-01

    Full Text Available Homosexual behavior has been analyzed as an evolutionary paradox in the biological context. In this review, we will try to compile the main genetic, epigenetic, hormonal, neurological and immune explanations of homosexuality, as well as the ultimate evolutionary causes of this complex behavior in the human being, incorporating information from studies in other animal species. All these factors determine the homosexual behavior, acting most of the times, simultaneously. Hereditary and non hereditary factors determine homosexual behavior, explaining its persistence despite its apparent disadvantages in relation to reproductive fitness.

  16. A neonatal mouse spinal cord injury model for assessing post-injury adaptive plasticity and human stem cell integration.

    Directory of Open Access Journals (Sweden)

    Jean-Luc Boulland

    Full Text Available Despite limited regeneration capacity, partial injuries to the adult mammalian spinal cord can elicit variable degrees of functional recovery, mediated at least in part by reorganization of neuronal circuitry. Underlying mechanisms are believed to include synaptic plasticity and collateral sprouting of spared axons. Because plasticity is higher in young animals, we developed a spinal cord compression (SCC injury model in the neonatal mouse to gain insight into the potential for reorganization during early life. The model provides a platform for high-throughput assessment of functional synaptic connectivity that is also suitable for testing the functional integration of human stem and progenitor cell-derived neurons being considered for clinical cell replacement strategies. SCC was generated at T9-T11 and functional recovery was assessed using an integrated approach including video kinematics, histology, tract tracing, electrophysiology, and high-throughput optical recording of descending inputs to identified spinal neurons. Dramatic degeneration of axons and synaptic contacts was evident within 24 hours of SCC, and loss of neurons in the injured segment was evident for at least a month thereafter. Initial hindlimb paralysis was paralleled by a loss of descending inputs to lumbar motoneurons. Within 4 days of SCC and progressively thereafter, hindlimb motility began to be restored and descending inputs reappeared, but with examples of atypical synaptic connections indicating a reorganization of circuitry. One to two weeks after SCC, hindlimb motility approached sham control levels, and weight-bearing locomotion was virtually indistinguishable in SCC and sham control mice. Genetically labeled human fetal neural progenitor cells injected into the injured spinal cord survived for at least a month, integrated into the host tissue and began to differentiate morphologically. This integrative neonatal mouse model provides opportunities to explore early

  17. Heterogeneities in local plastic flow behavior in a dissimilar weld between low-alloy steel and stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Mas, Fanny [Université Grenoble Alpes, SIMAP, 38000 Grenoble (France); CNRS, SIMAP, 38000 Grenoble (France); Martin, Guilhem, E-mail: guilhem.martin@simap.grenoble-inp.fr [Université Grenoble Alpes, SIMAP, 38000 Grenoble (France); CNRS, SIMAP, 38000 Grenoble (France); Lhuissier, Pierre; Bréchet, Yves; Tassin, Catherine [Université Grenoble Alpes, SIMAP, 38000 Grenoble (France); CNRS, SIMAP, 38000 Grenoble (France); Roch, François [Areva NP, Tour Areva, 92084 Paris La Défense (France); Todeschini, Patrick [EDF R& D, Avenue des Renardières, 77250 Moret-sur-Loing (France); Simar, Aude [Institute of Mechanics, Materials and Civil Engineering (iMMC), Université catholique de Louvain, 1348 Louvain-la-Neuve (Belgium)

    2016-06-14

    In dissimilar welds between low-alloy steel and stainless steel, the post-weld heat-treatment results in a high variety of microstructures coexisting around the fusion line, due to carbon diffusion and carbides dissolution/precipitation. The local constitutive laws in the vicinity of the fusion zone were identified by micro tensile specimens for the sub-millimeter sized zones, equivalent bulk materials representing the decarburized layer using both wet H{sub 2} atmosphere and diffusion couple, and nano-indentation for the carburized regions (i.e. the martensitic band and the austenitic region). The decarburized zone presents only 50% of the yield strength of the low-alloy steel heat affected zone and a ductility doubled. The carburized zones have a yield strength 3–5 times higher than that of the low-alloy steel heat affected zone and have almost no strain hardening capacity. These properties result in heterogeneous plastic deformation happening over only millimeters when the weld is loaded perpendicularly to the weld line, affecting its overall behavior. The constitutive laws experimentally identified were introduced as inputs into a finite elements model of the transverse tensile test performed on the whole dissimilar weld. A good agreement between experiments and simulations was achieved on the global stress-strain curve. The model also well predicts the local strain field measured by microscale DIC. A large out-of-plane deformation due to the hard carburized regions has also been identified.

  18. Plastic behavior of medium carbon vanadium microalloyed steel at temperatures near g « a transformation

    Directory of Open Access Journals (Sweden)

    Lourenço N.J.

    2001-01-01

    Full Text Available Dilatometric techniques were used to build the continuous cooling transformation (CCT diagram for a medium carbon microalloyed steel; the microstructure and hardness were determined at different cooling rates. The mechanical behavior of the steel in the austenite field and at temperatures approaching austenite to ferrite transformation was measured by means of hot torsion tests under isothermal and continuous cooling conditions. The no recrystallization temperatures, Tnr, and start of phase transformation, Ar3, were determined under continuous cooling condition using mean flow stress vs. inverse of absolute temperature diagrams. Interruption of static recrystallization within the interpass time in the austenite field indicated that the start of vanadium carbonitride precipitation occurred under 860 °C. Austenite transformation was found to start at around 710 °C, a temperature similar to that measured by dilatometry, suggesting that interphase precipitation delays the transformation of deformed austenite. Pearlite was observed at temperatures ranging from 650 °C to 600 °C, with the flow curves taking on a particular shape, i.e., stress rose sharply as strain was increased, reaching peak stress at low deformation, around 0.2, followed by an extensive softening region after peak stress.

  19. The development of human behavior analysis techniques

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Woon; Lee, Yong Hee; Park, Geun Ok; Cheon, Se Woo; Suh, Sang Moon; Oh, In Suk; Lee, Hyun Chul; Park, Jae Chang

    1997-07-01

    In this project, which is to study on man-machine interaction in Korean nuclear power plants, we developed SACOM (Simulation Analyzer with a Cognitive Operator Model), a tool for the assessment of task performance in the control rooms using software simulation, and also develop human error analysis and application techniques. SACOM was developed to assess operator`s physical workload, workload in information navigation at VDU workstations, and cognitive workload in procedural tasks. We developed trip analysis system including a procedure based on man-machine interaction analysis system including a procedure based on man-machine interaction analysis and a classification system. We analyzed a total of 277 trips occurred from 1978 to 1994 to produce trip summary information, and for 79 cases induced by human errors time-lined man-machine interactions. The INSTEC, a database system of our analysis results, was developed. The MARSTEC, a multimedia authoring and representation system for trip information, was also developed, and techniques for human error detection in human factors experiments were established. (author). 121 refs., 38 tabs., 52 figs.

  20. Human-Computer Interactions and Decision Behavior

    Science.gov (United States)

    1984-01-01

    software interfaces. The major components of the reseach program included the Diaiogue Management System. (DMS) operating environment, the role of...specification; and new methods for modeling, designing, and developing human-computer interfaces based on syntactic and semantic specification. The DMS...achieving communication is language. Accordingly, the transaction model employs a linguistic model consisting of parts that relate computer responses

  1. Effects of nanoparticle zinc oxide on spatial cognition and synaptic plasticity in mice with depressive-like behaviors

    Directory of Open Access Journals (Sweden)

    Xie Yongling

    2012-02-01

    Full Text Available Abstract Background Nanomaterials, as a new kind of materials, have been greatly applied in different fields due to their special properties. With the industrialization of nanostructured materials and increasing public exposure, the biosafety and potential influences on central nervous system (CNS have received more attention. Nanosized zinc oxide (nanoZnO was suggested to up-regulate neuronal excitability and to induce glutamate release in vitro. Therefore, we hypothesized nanoparticles of nanoZnO may lead to changes in balance of neurotransmitter or neuronal excitability of CNS. This study was to investigate if there were effects of nanoZnO on animal model of depression. Methods Male Swiss mice were given lipopolysaccharides (LPS, 100 μg/kg, 100 μg/ml, every other day, 8 times, i.p. from weaning to induce depressive-like behaviors. NanoZnO (5.6 mg/kg, 5.6 mg/ml, every other day, 8 times, i.p. was given as the interaction. The mouse model was characterized using the methods of open field test, tail suspension test and forced swim test. Furthermore, the spatial memory was evaluated using Morris water maze (MWM and the synaptic plasticity was assessed by measuring the long-term potentiation (LTP in the perforant pathway (PP to dentate gyrus (DG in vivo. Results Results indicated that model mice showed disrupted spatial memory and LTP after LPS injections and the behavioral and electrophysiological improvements after nanoZnO treatment. Conclusion Data suggested that nanoZnO may play some roles in CNS of mental disorders, which could provide some useful direction on the new drug exploring and clinical researches.

  2. [Advances in the experimental analysis of behavior: issues of choice behavior, comparative cognition, and human language].

    Science.gov (United States)

    Sakagami, T; Yamamoto, J; Jitsumori, M

    1994-12-01

    As the opportunity to contact with related areas has increased, the study of of the experimental analysis of behavior has experienced revolutionary changes. Some of the most active and important areas-studies of choice, comparative cognition, and human language--are reviewed to acquaint readers. Studies of CHOICE have linked to the molar theories of behavioral economics and behavioral ecology, which promoted research of choice by animals under uncertainty conditions. Further approach has been made to integrate the molar and molecular analyses on the basis of the ideas of behavior dynamics. COMPARATIVE COGNITION is a part of a larger field including cognitive science, behavioral neuroscience, and biological science. Recent developments, aided with a comparative perspective, made significant contributions to our understanding of the phylogeny and ontogeny of cognition. Advances in analysis of human behavior provided tools to study behavioral aspects of semantics, syntax, and pragmatics of HUMAN LANGUAGE. Using the paradigm of stimulus equivalence, the emergence of stimulus relations, stimulus-stimulus networks, hierarchical structure of verbal behavior, and other language-related behaviors have been investigated.

  3. Human Wagering Behavior Depends on Opponents' Faces

    Science.gov (United States)

    Schlicht, Erik J.; Shimojo, Shinsuke; Camerer, Colin F.; Battaglia, Peter; Nakayama, Ken

    2010-01-01

    Research in competitive games has exclusively focused on how opponent models are developed through previous outcomes and how peoples' decisions relate to normative predictions. Little is known about how rapid impressions of opponents operate and influence behavior in competitive economic situations, although such subjective impressions have been shown to influence cooperative decision-making. This study investigates whether an opponent's face influences players' wagering decisions in a zero-sum game with hidden information. Participants made risky choices in a simplified poker task while being presented opponents whose faces differentially correlated with subjective impressions of trust. Surprisingly, we find that threatening face information has little influence on wagering behavior, but faces relaying positive emotional characteristics impact peoples' decisions. Thus, people took significantly longer and made more mistakes against emotionally positive opponents. Differences in reaction times and percent correct were greatest around the optimal decision boundary, indicating that face information is predominantly used when making decisions during medium-value gambles. Mistakes against emotionally positive opponents resulted from increased folding rates, suggesting that participants may have believed that these opponents were betting with hands of greater value than other opponents. According to these results, the best “poker face” for bluffing may not be a neutral face, but rather a face that contains emotional correlates of trustworthiness. Moreover, it suggests that rapid impressions of an opponent play an important role in competitive games, especially when people have little or no experience with an opponent. PMID:20657772

  4. Induction of plasticity in the human motor cortex by pairing an auditory stimulus with TMS.

    Science.gov (United States)

    Sowman, Paul F; Dueholm, Søren S; Rasmussen, Jesper H; Mrachacz-Kersting, Natalie

    2014-01-01

    Acoustic stimuli can cause a transient increase in the excitability of the motor cortex. The current study leverages this phenomenon to develop a method for testing the integrity of auditorimotor integration and the capacity for auditorimotor plasticity. We demonstrate that appropriately timed transcranial magnetic stimulation (TMS) of the hand area, paired with auditorily mediated excitation of the motor cortex, induces an enhancement of motor cortex excitability that lasts beyond the time of stimulation. This result demonstrates for the first time that paired associative stimulation (PAS)-induced plasticity within the motor cortex is applicable with auditory stimuli. We propose that the method developed here might provide a useful tool for future studies that measure auditory-motor connectivity in communication disorders.

  5. Plasticity of human menstrual blood stem cells derived from the endometrium

    Institute of Scientific and Technical Information of China (English)

    Jian LIN; Dennis XIANG; Jin-long ZHANG; Julie ALLICKSON; Charlie XIANG

    2011-01-01

    Stem cells can be obtained from women's menstrual blood derived from the endometrium. The cells display stem cell markers such as Oct-4, SSEA-4, Nanog, and c-kit (CD117), and have the potent ability to differentiate into various cell types, including the heart, nerve, bone, cartilage, and fat. There has been no evidence of teratoma,ectopic formation, or any immune response after transplantation into an animal model. These cells quickly regenerate after menstruation and secrete many growth factors to display recurrent angiogenesis. The plasticity and safety of the acquired cells have been demonstrated in many studies. Menstrual blood-derived stem cells (MenSCs) provide an alternative source of adult stem cells for research and application in regenerative medicine. Here we summarize the multipotent properties and the plasticities of MenSCs and other endometrial stem cells from recent studies conducted both in vitro and in vivo.

  6. Induction of plasticity in the human motor cortex by pairing an auditory stimulus with TMS

    OpenAIRE

    Paul Fredrick Sowman; Jesper eRasmussen; Søren eDueholm; Natalie eMrachacz-Kersting

    2014-01-01

    Acoustic stimuli can cause a transient increase in the excitability of the motor cortex. The current study leverages this phenomenon to develop a method for testing the integrity of auditorimotor integration and the capacity for auditorimotor plasticity. We demonstrate that appropriately timed transcranial magnetic stimulation (TMS) of the hand area, paired with auditorily mediated excitation of the motor cortex, induces an enhancement of motor cortex excitability that lasts beyond the time o...

  7. Modeling Human Behavior to Anticipate Insider Attacks

    Energy Technology Data Exchange (ETDEWEB)

    Greitzer, Frank L.; Hohimer, Ryan E.

    2011-06-09

    The insider threat ranks among the most pressing cybersecurity challenges that threaten government and industry information infrastructures. To date, no systematic methods have been developed that provide a complete and effective approach to prevent data leakage, espionage and sabotage. Current practice is forensic in nature, relegating to the analyst the bulk of the responsibility to monitor, analyze, and correlate an overwhelming amount of data. We describe a predictive modeling framework that integrates a diverse set of data sources from the cyber domain as well as inferred psychological/motivational factors that may underlie malicious insider exploits. This comprehensive threat assessment approach provides automated support for the detection of high-risk behavioral “triggers” to help focus the analyst’s attention and inform the analysis. Designed to be domain independent, the system may be applied to many different threat and warning analysis/sensemaking problems.

  8. Modeling Human Behavior to Anticipate Insider Attacks

    Directory of Open Access Journals (Sweden)

    Ryan E Hohimer

    2011-01-01

    Full Text Available The insider threat ranks among the most pressing cyber-security challenges that threaten government and industry information infrastructures. To date, no systematic methods have been developed that provide a complete and effective approach to prevent data leakage, espionage, and sabotage. Current practice is forensic in nature, relegating to the analyst the bulk of the responsibility to monitor, analyze, and correlate an overwhelming amount of data. We describe a predictive modeling framework that integrates a diverse set of data sources from the cyber domain, as well as inferred psychological/motivational factors that may underlie malicious insider exploits. This comprehensive threat assessment approach provides automated support for the detection of high-risk behavioral "triggers" to help focus the analyst's attention and inform the analysis. Designed to be domain-independent, the system may be applied to many different threat and warning analysis/sense-making problems.

  9. Automated regional behavioral analysis for human brain images.

    Science.gov (United States)

    Lancaster, Jack L; Laird, Angela R; Eickhoff, Simon B; Martinez, Michael J; Fox, P Mickle; Fox, Peter T

    2012-01-01

    Behavioral categories of functional imaging experiments along with standardized brain coordinates of associated activations were used to develop a method to automate regional behavioral analysis of human brain images. Behavioral and coordinate data were taken from the BrainMap database (http://www.brainmap.org/), which documents over 20 years of published functional brain imaging studies. A brain region of interest (ROI) for behavioral analysis can be defined in functional images, anatomical images or brain atlases, if images are spatially normalized to MNI or Talairach standards. Results of behavioral analysis are presented for each of BrainMap's 51 behavioral sub-domains spanning five behavioral domains (Action, Cognition, Emotion, Interoception, and Perception). For each behavioral sub-domain the fraction of coordinates falling within the ROI was computed and compared with the fraction expected if coordinates for the behavior were not clustered, i.e., uniformly distributed. When the difference between these fractions is large behavioral association is indicated. A z-score ≥ 3.0 was used to designate statistically significant behavioral association. The left-right symmetry of ~100K activation foci was evaluated by hemisphere, lobe, and by behavioral sub-domain. Results highlighted the classic left-side dominance for language while asymmetry for most sub-domains (~75%) was not statistically significant. Use scenarios were presented for anatomical ROIs from the Harvard-Oxford cortical (HOC) brain atlas, functional ROIs from statistical parametric maps in a TMS-PET study, a task-based fMRI study, and ROIs from the ten "major representative" functional networks in a previously published resting state fMRI study. Statistically significant behavioral findings for these use scenarios were consistent with published behaviors for associated anatomical and functional regions.

  10. Music-induced cortical plasticity and lateral inhibition in the human auditory cortex as foundations for tonal tinnitus treatment

    Directory of Open Access Journals (Sweden)

    Christo ePantev

    2012-06-01

    Full Text Available Over the past 15 years, we have studied plasticity in the human auditory cortex by means of magnetoencephalography (MEG. Two main topics nurtured our curiosity: the effects of musical training on plasticity in the auditory system, and the effects of lateral inhibition. One of our plasticity studies found that listening to notched music for three hours inhibited the neuronal activity in the auditory cortex that corresponded to the center-frequency of the notch, suggesting suppression of neural activity by lateral inhibition. Crucially, the overall effects of lateral inhibition on human auditory cortical activity were stronger than the habituation effects. Based on these results we developed a novel treatment strategy for tonal tinnitus - tailor-made notched music training (TMNMT. By notching the music energy spectrum around the individual tinnitus frequency, we intended to attract lateral inhibition to auditory neurons involved in tinnitus perception. So far, the training strategy has been evaluated in two studies. The results of the initial long-term controlled study (12 months supported the validity of the treatment concept: subjective tinnitus loudness and annoyance were significantly reduced after TMNMT but not when notching spared the tinnitus frequencies. Correspondingly, tinnitus-related auditory evoked fields (AEFs were significantly reduced after training. The subsequent short-term (5 days training study indicated that training was more effective in the case of tinnitus frequencies ≤ 8 kHz compared to tinnitus frequencies > 8 kHz, and that training should be employed over a long-term in order to induce more persistent effects. Further development and evaluation of TMNMT therapy are planned. A goal is to transfer this novel, completely non-invasive, and low-cost treatment approach for tonal tinnitus into routine clinical practice.

  11. PRENATAL HYPOXIA IN DIFFERENT PERIODS OF EMBRYOGENESIS DIFFERENTIALLY AFFECTS CELL MIGRATION, NEURONAL PLASTICITY AND RAT BEHAVIOR IN POSTNATAL ONTOGENESIS

    Directory of Open Access Journals (Sweden)

    Dmitrii S Vasilev

    2016-03-01

    , affects formation of cortical cytoarchitecture, neuronal plasticity and behavior in postnatal ontogenesis which testify to cortical dysfunction. Hypoxia on E18 does not significantly affect cortical structure and parietal cortex-dependent behavioral tasks.

  12. Timing of Multimodal Robot Behaviors during Human-Robot Collaboration

    DEFF Research Database (Denmark)

    Jensen, Lars Christian; Fischer, Kerstin; Suvei, Stefan-Daniel

    2017-01-01

    In this paper, we address issues of timing between robot behaviors in multimodal human-robot interaction. In particular, we study what effects sequential order and simultaneity of robot arm and body movement and verbal behavior have on the fluency of interactions. In a study with the Care...... output plays a special role because participants carry their expectations from human verbal interaction into the interactions with robots.......-O-bot, a large service robot, in a medical measurement scenario, we compare the timing of the robot's behaviors in three between-subject conditions. The results show that the relative timing of robot behaviors has significant effects on the number of problems participants encounter, and that the robot's verbal...

  13. L\\'evy flights in human behavior and cognition

    CERN Document Server

    Baronchelli, Andrea

    2013-01-01

    L\\'evy flights represent the best strategy to randomly search for a target in an unknown environment, and have been widely observed in many animal species. Here, we inspect and discuss recent results concerning human behavior and cognition. Different studies have shown that human mobility can be described in terms of L\\'evy flights, while fresh evidence indicates that the same pattern accounts for human mental searches in online gambling sites. Thus, L\\'evy flights emerge as a unifying concept with broad cross-disciplinary implications. We argue that the ubiquity of such a pattern, both in behavior and cognition, suggests that the brain regions responsible for this behavior are likely to be evolutionarily old (i.e. no frontal cortex is involved), and that fMRI techniques might help to confirm this hypothesis.

  14. Plastic Pollution from Ships

    OpenAIRE

    Čulin, Jelena; Bielić, Toni

    2016-01-01

    The environmental impact of shipping on marine environment includes discharge of garbage. Plastic litter is of particular concern due to abundance, resistance to degradation and detrimental effect on marine biota. According to recently published studies, a further research is required to assess human health risk. Monitoring data indicate that despite banning plastic disposal at sea, shipping is still a source of plastic pollution. Some of the measures to combat the problem are discussed.

  15. Smoking and alcoholism target genes associated with plasticity and glutamate transmission in the human ventral tegmental area.

    Science.gov (United States)

    Flatscher-Bader, T; Zuvela, N; Landis, N; Wilce, P A

    2008-01-01

    Drugs of abuse including nicotine and alcohol elicit their effect by stimulating the mesocorticolimbic dopaminergic system. There is a high incidence of nicotine dependence in alcoholics. To date only limited data is available on the molecular mechanism underlying the action of alcohol and nicotine in the human brain. This study utilized gene expression screening to identify genes sensitive to chronic alcohol abuse within the ventral tegmental area (VTA) of the human brain. Alcohol-responsive genes encoded proteins primarily involved in structural plasticity and neurotransmitter transport and release. In particular, genes involved with brain-derived neurotrophic factor signalling and glutamatergic transmission were found to be affected. The possibility that glutamate transport was a target of chronic alcohol and/or tobacco abuse was further investigated in an extended case set by measurement of mRNA and protein expression. Expression levels of vesicular glutamate transporters SLC17A6 and SLC17A7 were robustly induced by smoking, an effect that was reduced by alcohol co-exposure. Glutamatergic transmission is vital for the control of the VTA and may also be critical to the weighting of novelty and importance of a stimulus, an essential output of this brain region. We conclude that enduring plasticity within the VTA may be a major molecular mechanism for the maintenance of smoking addiction and that alcohol, nicotine and co-abuse have distinct impacts on glutamatergic transmission with important implications for the control of this core mesolimbic structure.

  16. Talking with a Virtual Human: Controlling the Human Experience and Behavior in a Virtual Conversation

    NARCIS (Netherlands)

    Qu, C.

    2014-01-01

    Virtual humans are often designed to replace real humans in virtual reality applications for e.g., psychotherapy, education and entertainment. In general, applications with virtual humans are created for modifying a person's knowledge, beliefs, attitudes, emotions or behaviors. Reaching these intend

  17. State dissociation, human behavior, and consciousness.

    Science.gov (United States)

    Mahowald, Mark W; Cramer Bornemann, Michel A; Schenck, Carlos H

    2011-01-01

    Sleep is clearly not only a whole-brain or global phenomenon, but can also be a local phenomenon. This accounts for the fact that the primary states of being (wakefulness, NREM sleep, and REM sleep) are not necessarily mutually exclusive, and components of these states may appear in various combinations, with fascinating clinical consequences. Examples include: sleep inertia, narcolepsy, sleep paralysis, lucid dreaming, REM sleep behavior disorder, sleepwalking, sleep terrors, out-of-body experiences, and reports of alien abduction. The incomplete declaration of state likewise has implications for consciousness - which also has fluid boundaries. Fluctuations in the degree of consciousness are likely explained by abnormalities of a "spatial and temporal binding rhythm" which normally results in a unified conscious experience. Dysfunctional binding may play a role in anesthetic states, autism, schizophrenia, and neurodegenerative disorders. Further study of the broad spectrum of dissociated states of sleep and wakefulness that are closely linked with states of consciousness and unconsciousness by basic neuroscientists, clinicians, and members of the legal profession will provide scientific, clinical and therapeutic insights, with forensic implications.

  18. Highly plastic behavior and fluidization of gouge; implications for fault and landslide mechanics and for the generation of mud volcanoes

    Science.gov (United States)

    Shimamoto, Toshihiko; Aoki, Kazuhiro; Seshimo, Kazuyoshi; Hu, Wei; Ma, Shengli; Yao, Lu; Xiong, Ran; Xiao, Yinke

    2016-04-01

    We address an issue on "how low gouge friction can be with an increasing amount of pore fluid" (an unexplored problem in fault mechanics), as studied with a rotary-shear low to high-velocity friction apparatus in Beijing using host specimens of Ti-Al-V alloy with a Teflon sleeve. A friction experiment was conducted on about 1 mm-thick, smectite-rich gouge from Shionohira fault zone, Fukushima, Japan, with 80 wt% of initial pore water, at a normal stress of 1 MPa, and with velocity steps of 17 times ranging in 0.21 microns/s to 2.1 m/s. Friction coefficients at slow rates were initially 0.003 to 0.005 with abundant water, but the coefficients increased to about 0.2 owing to the loss of water during the drained tests. Gouge was squeezed out slowly from host-specimen/Teflon interface as very thin paper-like flakes during a part of the run, indicating highly plastic behavior of gouge. The initial friction was by far the lowest ever reported! A dry high-velocity friction experiment on the same gouge (normal stress 2 MPa, velocity 2.1 m/s) revealed fluidization of gouge due to vaporized water released during decomposition of clay minerals. Friction coefficient increased to its peak (~ 0.8), followed by nearly exponential decay to a steady-state value of ~ 0.2. Then the friction coefficient began to decrease almost linearly with displacement down to ca. 0.07, deviating from an exponential decay. The gouge was lost almost instantly in less than one second, terminating the run. Temperature, measured at the sliding surface, began to decrease at the onset of the nearly linear weakening, strongly suggesting dehydration of clays (endothermic reactions). We interpret the results that steam pressure increased in gouge till a limit to cause a small explosion of gouge. Gouge can fluidize! A series of low to intermediate-velocity experiments on slip-zone materials from Kualiangzi landslide, Sichuan, China, demonstrated that the initial friction coefficient was less than 0.1 with a

  19. Methylphenidate administration to adolescent rats determines plastic changes on reward-related behavior and striatal gene expression.

    Science.gov (United States)

    Adriani, Walter; Leo, Damiana; Greco, Dario; Rea, Monica; di Porzio, Umberto; Laviola, Giovanni; Perrone-Capano, Carla

    2006-09-01

    Administration of methylphenidate (MPH, Ritalin) to children with attention deficit hyperactivity disorder (ADHD) is an elective therapy, but raises concerns for public health, due to possible persistent neurobehavioral alterations. Wistar adolescent rats (30 to 46 day old) were administered MPH or saline (SAL) for 16 days, and tested for reward-related and motivational-choice behaviors. When tested in adulthood in a drug-free state, MPH-pretreated animals showed increased choice flexibility and economical efficiency, as well as a dissociation between dampened place conditioning and more marked locomotor sensitization induced by cocaine, compared to SAL-pretreated controls. The striatal complex, a core component of the natural reward system, was collected both at the end of the MPH treatment and in adulthood. Genome-wide expression profiling, followed by RT-PCR validation on independent samples, showed that three members of the postsynaptic-density family and five neurotransmitter receptors were upregulated in the adolescent striatum after subchronic MPH administration. Interestingly, only genes for the kainate 2 subunit of ionotropic glutamate receptor (Grik2, also known as KA2) and the 5-hydroxytryptamine (serotonin) receptor 7 (Htr7) (but not GABA(A) subunits and adrenergic receptor alpha1b) were still upregulated in adulthood. cAMP responsive element-binding protein and Homer 1a transcripts were modulated only as a long-term effect. In summary, our data indicate short-term changes in neural plasticity, suggested by modulation of expression of key genes, and functional changes in striatal circuits. These modifications might in turn trigger enduring changes responsible for the adult neurobehavioral profile, that is, altered processing of incentive values and a modified flexibility/habit balance.

  20. Dose-response curve of associative plasticity in human motor cortex and interactions with motor practice.

    Science.gov (United States)

    Elahi, Behzad; Hutchison, William D; Daskalakis, Z Jeff; Gunraj, Carolyn; Chen, Robert

    2014-02-01

    Associative plasticity is hypothesized to be an important neurophysiological correlate of memory formation and learning with potentials for applications in neurorehabilitation and for the development of new electrophysiological measures to study disorders of cortical plasticity. We hypothesized that the magnitude of the paired associative stimulation (PAS)-induced long-term potentiation (LTP)-like effect depends on the number of pairs in the PAS protocol. We also hypothesized that homeostatic interaction of PAS with subsequent motor learning is related to the magnitude of the PAS-induced LTP-like effect. We studied 10 healthy subjects. In experiment 1a, subjects received 90 (PAS90), 180 (PAS180), or 270 (PAS270) pairs of stimuli, followed by a dynamic motor practice (DMP) 1 h after the end of the PAS protocols. In experiment 1b, the DMP preceded the PAS protocol. In experiment 2, the time course of PAS270 was studied. We found that PAS270 resulted in greater increase in motor evoked potential (MEP) amplitude compared with protocols with fewer pairs of stimuli. Moreover, the interaction between PAS protocols with motor learning differed depending on the number of stimulus pairs used to induce PAS. While DMP alone increased MEP amplitudes, DMP during the LTP-like effects induced by PAS270 led to a long-term depression (LTD)-like effect (homeostatic interaction). This homeostatic interaction did not occur after PAS90 and PAS180. In conclusion, we found a dose-dependent effect of the number of stimulus pairs used in the PAS protocol on cortical plasticity. Homeostatic interaction between PAS and DMP was observed only after PAS270.

  1. Social performance cues induce behavioral flexibility in humans

    Directory of Open Access Journals (Sweden)

    Ulf eToelch

    2011-07-01

    Full Text Available Behavioral flexibility allows individuals to react to environmental changes, but changing established behavior carries costs, with unknown benefits. Individuals may thus modify their behavioral flexibility according to the prevailing circumstances. Social information provided by the performance level of others provides one possible cue to assess the potential benefits of changing behavior, since out-performance in similar circumstances indicates that novel behaviors (innovations are potentially useful. We demonstrate that social performance cues, in the form of previous players’ scores in a problem-solving computer game, influence behavioral flexibility. Participants viewed only performance indicators, not the innovative behavior of others. While performance cues (high, low, or no scores had little effect on innovation discovery rates, participants that viewed high scores increased their utilization of innovations, allowing them to exploit the virtual environment more effectively than players viewing low or no scores. Perceived conspecific performance can thus shape human decisions to adopt novel traits, even when the traits employed cannot be copied. This simple mechanism, social performance feedback, could be a driver of both the facultative adoption of innovations and cumulative cultural evolution, processes critical to human success.

  2. Collective unconscious: how gut microbes shape human behavior.

    Science.gov (United States)

    Dinan, Timothy G; Stilling, Roman M; Stanton, Catherine; Cryan, John F

    2015-04-01

    The human gut harbors a dynamic and complex microbial ecosystem, consisting of approximately 1 kg of bacteria in the average adult, approximately the weight of the human brain. The evolutionary formation of a complex gut microbiota in mammals has played an important role in enabling brain development and perhaps sophisticated social interaction. Genes within the human gut microbiota, termed the microbiome, significantly outnumber human genes in the body, and are capable of producing a myriad of neuroactive compounds. Gut microbes are part of the unconscious system regulating behavior. Recent investigations indicate that these microbes majorly impact on cognitive function and fundamental behavior patterns, such as social interaction and stress management. In the absence of microbes, underlying neurochemistry is profoundly altered. Studies of gut microbes may play an important role in advancing understanding of disorders of cognitive functioning and social interaction, such as autism.

  3. HUMAN RESOURCE MANAGEMENT IN TERMS OF BEHAVIORAL ECONOMICS

    Directory of Open Access Journals (Sweden)

    Ewa Mazanowska

    2015-01-01

    Full Text Available Behaviourists believe human capital is seen as the potential in people. They believe that the human resource in the organization are intangible assets embodied in the employees, not the people themselves. Behavioral economics emphasizes that people aren’t owned by the company, only their abilities and skills made available to the employer on the basis of certain legal relations which holds it to manage these assets in a rational way. Recognition of behavioral economics also highlights the aspects of development and human capital perspective, which appear in the may resource Staff in the future. These may be limited to: raise, awareness of capacity, internal aspirations, motives. Human capital management is nothing but a recognition of the relevant characteristics of the potential held within the company Staff and correct its use. As a consequence, it can bring tangible benefits to the organization.

  4. Consciousness, plasticity, and connectomics: the role of intersubjectivity in human cognition

    DEFF Research Database (Denmark)

    Allen, Micah Galen; Williams, Gary

    2011-01-01

    Consciousness is typically construed as being explainable purely in terms of either private, raw feels or higher-order, reflective representations. In contrast to this false dichotomy, we propose a new view of consciousness as an interactive, plastic phenomenon open to sociocultural influence. We...... by encultured social practices that depend upon and influence phenomenal and reflective consciousness. On our account, the dynamically interacting connectivity of these networks bring about important individual differences in conscious experience and determine what is “present” in consciousness. Further, we...

  5. Do estrogenic compounds in drinking water migrating from plastic pipe distribution system pose adverse effects to human? An analysis of scientific literature.

    Science.gov (United States)

    Liu, Ze-Hua; Yin, Hua; Dang, Zhi

    2017-01-01

    With the widespread application of plastic pipes in drinking water distribution system, the effects of various leachable organic chemicals have been investigated and their occurrence in drinking water supplies is monitored. Most studies focus on the odor problems these substances may cause. This study investigates the potential endocrine disrupting effects of the migrating compound 2,4-di-tert-butylphenol (2,4-d-t-BP). The summarized results show that the migration of 2,4-d-t-BP from plastic pipes could result in chronic exposure and the migration levels varied greatly among different plastic pipe materials and manufacturing brands. Based on estrogen equivalent (EEQ), the migrating levels of the leachable compound 2,4-d-t-BP in most plastic pipes were relative low. However, the EEQ levels in drinking water migrating from four out of 15 pipes may pose significant adverse effects. With the increasingly strict requirements on regulation of drinking water quality, these results indicate that some drinking water transported with plastic pipes may not be safe for human consumption due to the occurrence of 2,4-d-t-BP. Moreover, 2,4-d-t-BP is not the only plastic pipe-migrating estrogenic compound, other compounds such as 2-tert-butylphenol (2-t-BP), 4-tert-butylphenol (4-t-BP), and others may also be leachable from plastic pipes.

  6. Synaptic Plasticity and Learning Behaviors Mimicked in Single Inorganic Synapses of Pt/HfOx/ZnOx/TiN Memristive System

    Science.gov (United States)

    Wang, Lai-Guo; Zhang, Wei; Chen, Yan; Cao, Yan-Qiang; Li, Ai-Dong; Wu, Di

    2017-01-01

    In this work, a kind of new memristor with the simple structure of Pt/HfOx/ZnOx/TiN was fabricated completely via combination of thermal-atomic layer deposition (TALD) and plasma-enhanced ALD (PEALD). The synaptic plasticity and learning behaviors of Pt/HfOx/ZnOx/TiN memristive system have been investigated deeply. Multilevel resistance states are obtained by varying the programming voltage amplitudes during the pulse cycling. The device conductance can be continuously increased or decreased from cycle to cycle with better endurance characteristics up to about 3 × 103 cycles. Several essential synaptic functions are simultaneously achieved in such a single double-layer of HfOx/ZnOx device, including nonlinear transmission properties, such as long-term plasticity (LTP), short-term plasticity (STP), and spike-timing-dependent plasticity. The transformation from STP to LTP induced by repetitive pulse stimulation is confirmed in Pt/HfOx/ZnOx/TiN memristive device. Above all, simple structure of Pt/HfOx/ZnOx/TiN by ALD technique is a kind of promising memristor device for applications in artificial neural network.

  7. MALADAPTIVE PLASTICITY IN LEVODOPA-INDUCED DYSKINESIAS AND TARDIVE DYSKINESIAS: OLD AND NEW INSIGHTS ON THE EFFECTS OF DOPAMINE RECEPTOR PHARMACOLOGY

    OpenAIRE

    Antonio eCerasa; Alfonso eFasano; Francesca eMorgante; Giacomo eKoch; Aldo eQuattrone

    2014-01-01

    Maladaptive plasticity can be defined as behavioral loss or even development of disease symptoms resulting from aberrant plasticity changes in the human brain. Hyperkinetic movement disorders, either in the neurological or psychiatric realms, have been associated with maladaptive neural plasticity that can be expressed by functional changes such as an increase in transmitter release, receptor regulation and synaptic plasticity or anatomical modifications such as axonal regeneration, sprouting...

  8. Maladaptive Plasticity in Levodopa-Induced Dyskinesias and Tardive Dyskinesias: Old and New Insights on the Effects of Dopamine Receptor Pharmacology

    OpenAIRE

    Cerasa, Antonio; Fasano, Alfonso; Morgante, Francesca; Koch, Giacomo; Quattrone, Aldo

    2014-01-01

    Maladaptive plasticity can be defined as behavioral loss or even development of disease symptoms resulting from aberrant plasticity changes in the human brain. Hyperkinetic movement disorders, in the neurological or psychiatric realms, have been associated with maladaptive neural plasticity that can be expressed by functional changes such as an increase in transmitter release, receptor regulation, and synaptic plasticity or anatomical modifications such as axonal regeneration, sprouting, syna...

  9. Novelty, Stress, and Biological Roots in Human Market Behavior

    Directory of Open Access Journals (Sweden)

    Alexey Sarapultsev

    2014-02-01

    Full Text Available Although studies examining the biological roots of human behavior have been conducted since the seminal work Kahneman and Tversky, crises and panics have not disappeared. The frequent occurrence of various types of crises has led some economists to the conviction that financial markets occasionally praise irrational judgments and that market crashes cannot be avoided a priori (Sornette 2009; Smith 2004. From a biological point of view, human behaviors are essentially the same during crises accompanied by stock market crashes and during bubble growth when share prices exceed historic highs. During those periods, most market participants see something new for themselves, and this inevitably induces a stress response in them with accompanying changes in their endocrine profiles and motivations. The result is quantitative and qualitative changes in behavior (Zhukov 2007. An underestimation of the role of novelty as a stressor is the primary shortcoming of current approaches for market research. When developing a mathematical market model, it is necessary to account for the biologically determined diphasisms of human behavior in everyday low-stress conditions and in response to stressors. This is the only type of approach that will enable forecasts of market dynamics and investor behaviors under normal conditions as well as during bubbles and panics.

  10. Novelty, stress, and biological roots in human market behavior.

    Science.gov (United States)

    Sarapultsev, Alexey; Sarapultsev, Petr

    2014-03-01

    Although studies examining the biological roots of human behavior have been conducted since the seminal work Kahneman and Tversky, crises and panics have not disappeared. The frequent occurrence of various types of crises has led some economists to the conviction that financial markets occasionally praise irrational judgments and that market crashes cannot be avoided a priori (Sornette 2009; Smith 2004). From a biological point of view, human behaviors are essentially the same during crises accompanied by stock market crashes and during bubble growth when share prices exceed historic highs. During those periods, most market participants see something new for themselves, and this inevitably induces a stress response in them with accompanying changes in their endocrine profiles and motivations. The result is quantitative and qualitative changes in behavior (Zhukov 2007). An underestimation of the role of novelty as a stressor is the primary shortcoming of current approaches for market research. When developing a mathematical market model, it is necessary to account for the biologically determined diphasisms of human behavior in everyday low-stress conditions and in response to stressors. This is the only type of approach that will enable forecasts of market dynamics and investor behaviors under normal conditions as well as during bubbles and panics.

  11. The interaction between ICT and human activity-travel behavior

    NARCIS (Netherlands)

    Kwan, M.P.; Dijst, M.J.; Schwanen, T.

    2007-01-01

    The interaction between information and communication technologies (ICT) and human activity-travel behavior has been an important theme in transportation research in recent years. Researchers have recognized that an increase in the use of ICT may lead to changes in the location, timing and duration

  12. Measuring Human Movement Patterns and Behaviors in Public Spaces

    DEFF Research Database (Denmark)

    Nielsen, Søren Zebitz; Gade, Rikke; Moeslund, Thomas B.;

    In order to assess human movement patterns and behaviors in public spaces we present a method using thermal cameras and Computer Vision (CV) technology, combined with the analytical virtues of Geographical Information Systems (GIS), to track people in urban streets and plazas. The method enables...

  13. Industrial Buying Behavior Related to Human Resource Consulting Services

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe; Hollensen, Svend; Kahle, Lynn

    2013-01-01

    The purpose of this article is to extend the understanding of the industrial buying process in connection with purchasing professional business (B2B) services, specifically human resource (HR) consulting services. Early B2B buying-behavior literature strongly emphasizes the rational aspects...

  14. Industrial Buying Behavior Related to Human Resource Consulting Services

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe; Hollensen, Svend; Kahle, Lynn

    2013-01-01

    The purpose of this article is to extend the understanding of the industrial buying process in connection with purchasing professional business (B2B) services, specifically human resource (HR) consulting services. Early B2B buying-behavior literature strongly emphasizes the rational aspects...

  15. Counseling Children and Adolescents: Rational Emotive Behavior Therapy and Humanism.

    Science.gov (United States)

    Vernon, Ann

    1996-01-01

    Describes specific parallels between rational emotive behavior therapy and humanism. Places specific emphasis on the application of these principles with children and adolescents. Concepts are illustrated with case studies and a description of the similarities between rational emotive and humanistic, or affective, education. Highlights emotional…

  16. The interaction between ICT and human activity-travel behavior

    NARCIS (Netherlands)

    Kwan, M.P.; Dijst, M.J.; Schwanen, T.

    2007-01-01

    The interaction between information and communication technologies (ICT) and human activity-travel behavior has been an important theme in transportation research in recent years. Researchers have recognized that an increase in the use of ICT may lead to changes in the location, timing and duration

  17. Interactive human behavior analysis in open or public spaces

    NARCIS (Netherlands)

    Hung, H.; Odobez, J.M.; Gavrila, D.M.

    2011-01-01

    In the past years, efforts in surveillance and open space analysis have focused on traditional computer vision problems like scene modeling or object detection and tracking. Research on human behavior recognition have tended to work on predefined simple activities such as running, jumping or left lu

  18. Cognitive Empathy and Emotional Empathy in Human Behavior and Evolution

    Science.gov (United States)

    Smith, Adam

    2006-01-01

    This article presents 7 simple models of the relationship between cognitive empathy (mental perspective taking) and emotional empathy (the vicarious sharing of emotion). I consider behavioral outcomes of the models, arguing that, during human evolution, natural selection may have acted on variation in the relationship between cognitive empathy and…

  19. Common Fallacies About Heredity, Environment, and Human Behavior.

    Science.gov (United States)

    Anastasi, Anne

    Much of our thinking about contemporary social problems reflects tacit presuppositions regarding the operation of heredity and environment in human behavior. These beliefs have important implications for practical decisions. Advances in genetics, psychology, anthropology, and other disciplines have contributed much to a clarification of the…

  20. Counseling Children and Adolescents: Rational Emotive Behavior Therapy and Humanism.

    Science.gov (United States)

    Vernon, Ann

    1996-01-01

    Describes specific parallels between rational emotive behavior therapy and humanism. Places specific emphasis on the application of these principles with children and adolescents. Concepts are illustrated with case studies and a description of the similarities between rational emotive and humanistic, or affective, education. Highlights emotional…

  1. Cognitive Empathy and Emotional Empathy in Human Behavior and Evolution

    Science.gov (United States)

    Smith, Adam

    2006-01-01

    This article presents 7 simple models of the relationship between cognitive empathy (mental perspective taking) and emotional empathy (the vicarious sharing of emotion). I consider behavioral outcomes of the models, arguing that, during human evolution, natural selection may have acted on variation in the relationship between cognitive empathy and…

  2. Plasticity theory

    CERN Document Server

    Lubliner, Jacob

    2008-01-01

    The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and

  3. Human Behavior Recognition Using Foot Pressure Sensing Shoes

    Science.gov (United States)

    Sugimoto, Chika; Ozaki, Kenji; Ezoe, Ryosuke; Hosaka, Hiroshi; Yamato, Hiroyuki

    To recognize human behavior in unlimited environments, sensing shoes for measuring foot pressure distribution were developed. Seven pressure sensors were installed on an insole, and a measurement module was embedded in the shoe. An analysis for discriminating the user's movements from the foot pressure distribution was examined, considering the movements, walking, running, standing, sitting, going upstairs and downstairs, and cycling. These seven actions were discriminated using feature quantities such as the average, standard deviation, maximum, and difference deviation extracted from the data of three sensors by discriminant analysis. The evaluation results showed highly accurate behavior recognition based on foot pressure at some points. In addition, by canonical discriminant analysis, six discriminant functions which classify the seven actions with an accuracy of 100% were derived by using feature quantities extracted from five sensors. The results confirmed that discriminant analysis can be used for automatically recognizing human behaviors based on foot pressure data.

  4. Plasticity of marrow mesenchymal stem cells from human first-trimester fetus: from single-cell clone to neuronal differentiation.

    Science.gov (United States)

    Zhang, Yihua; Shen, Wenzheng; Sun, Bingjie; Lv, Changrong; Dou, Zhongying

    2011-02-01

    Recent results have shown that bone marrow mesenchymal stem cells (BMSCs) from human first-trimester abortus (hfBMSCs) are closer to embryonic stem cells and perform greater telomerase activity and faster propagation than mid- and late-prophase fetal and adult BMSCs. However, no research has been done on the plasticity of hfBMSCs into neuronal cells using single-cell cloned strains without cell contamination. In this study, we isolated five single cells from hfBMSCs and obtained five single-cell cloned strains, and investigated their biological property and neuronal differentiation potential. We found that four of the five strains showed similar expression profile of surface antigen markers to hfBMSCs, and most of them differentiated into neuron-like cells expressing Nestin, Pax6, Sox1, β-III Tubulin, NF-L, and NSE under induction. One strain showed different expression profile of surface antigen markers from the four strains and hfBMSCs, and did not differentiate toward neuronal cells. We demonstrated for the first time that some of single-cell cloned strains from hfBMSCs can differentiate into nerve tissue-like cell clusters under induction in vitro, and that the plasticity of each single-cell cloned strain into neuronal cells is different.

  5. Simulating plastic surgery: from human skin tensile tests, through hyperelastic finite element models to real-time haptics.

    Science.gov (United States)

    Lapeer, R J; Gasson, P D; Karri, V

    2010-12-01

    In this paper, we provide a summary of a number of experiments we conducted to arrive at a prototype real-time simulator for plastic surgical interventions such as skin flap repair and inguinal herniotomy. We started our research with a series of in-vitro tensile stress tests on human skin, harvested from female patients undergoing plastic reconstructive surgery. We then used the acquired stress-strain data to fit hyperelastic models. Three models were considered: General Polynomial, Reduced Polynomial and Ogden. Only Reduced Polynomial models were found to be stable, hence they progressed to the next stage to be used in an explicit finite element model aimed at real-time performance in conjunction with a haptic feedback device. A total Lagrangian formulation with the half-step central difference method was employed to integrate the dynamic equation of motion of the mesh. The mesh was integrated into two versions of a real-time skin simulator: a single-threaded version running on a computer's main central processing unit and a multi-threaded version running on the computer's graphics card. The latter was achieved by exploiting recent advances in programmable graphics technology.

  6. Plastics and health risks.

    Science.gov (United States)

    Halden, Rolf U

    2010-01-01

    By 2010, the worldwide annual production of plastics will surpass 300 million tons. Plastics are indispensable materials in modern society, and many products manufactured from plastics are a boon to public health (e.g., disposable syringes, intravenous bags). However, plastics also pose health risks. Of principal concern are endocrine-disrupting properties, as triggered for example by bisphenol A and di-(2-ethylhexyl) phthalate (DEHP). Opinions on the safety of plastics vary widely, and despite more than five decades of research, scientific consensus on product safety is still elusive. This literature review summarizes information from more than 120 peer-reviewed publications on health effects of plastics and plasticizers in lab animals and humans. It examines problematic exposures of susceptible populations and also briefly summarizes adverse environmental impacts from plastic pollution. Ongoing efforts to steer human society toward resource conservation and sustainable consumption are discussed, including the concept of the 5 Rs--i.e., reduce, reuse, recycle, rethink, restrain--for minimizing pre- and postnatal exposures to potentially harmful components of plastics.

  7. Detecting Underlying Stance Adopted When Human Construe Behavior of Entities

    Science.gov (United States)

    Terada, Kazunori; Ono, Kouhei; Ito, Akira

    Whether or not humans can construe the behaviors of entities depends on their psychological stance. The philosopher Dennett proposed human cognitive strategies (three stances) in which humans construe the behavior of other animated objects, including other humans, artifacts, and physical phenomena:‘intentional’, ‘design’ and ‘physical’ stances. Detecting the psychological stance taken toward entities is difficult, because such mental state attribution is a subjective cognitive process and hard to measure. In the present study, we proposed a novel method for detecting underlying stance adopted when human construe behavior of entities. In our method the subject was asked to select the most suitable action sequence shown in three movies each of which representing Dennett’s three stances. To valid our method we have conducted an experiment in which the subjects were presented thirty short videos and asked to compare them to the three movies. The result indicated that the subjects did not focused on prior knowledge about the entity but could focused on motion characteristics per se, owing to simple and typical motion of an abstract shaped object.

  8. Human Papillomavirus Vaccination at a Time of Changing Sexual Behavior.

    Science.gov (United States)

    Baussano, Iacopo; Lazzarato, Fulvio; Brisson, Marc; Franceschi, Silvia

    2016-01-01

    Human papillomavirus (HPV) prevalence varies widely worldwide. We used a transmission model to show links between age-specific sexual patterns and HPV vaccination effectiveness. We considered rural India and the United States as examples of 2 heterosexual populations with traditional age-specific sexual behavior and gender-similar age-specific sexual behavior, respectively. We simulated these populations by using age-specific rates of sexual activity and age differences between sexual partners and found that transitions from traditional to gender-similar sexual behavior in women sexual behavior and that increased risk for HPV infection attributable to transition is preventable by early vaccination. Our study highlights the importance of using time-limited opportunities to introduce HPV vaccination in traditional populations before changes in age-specific sexual patterns occur.

  9. MEASUREMENT OF PHTHALATE LEVELS IN HUMAN MILK: CONTRIBUTION FROM PLASTICS IN BREAST PUMPS, STORAGE BOTTLES AND BAGS

    Science.gov (United States)

    Phthalates are plasticizers used to impart flexibility in products widely used by the general population, including polyvinyl chloride, plastic toys, and medical devices. Some phthalates act as anti-androgens, and prenatal or perinatal exposure to phthalates in laboratory animals...

  10. Study on Customer Plastic Medical Searching Behavior of Different Plastic Medical Institutions%不同类型整形医疗机构顾客寻医行为现状探讨

    Institute of Scientific and Technical Information of China (English)

    张鹤明; 杜俊峰; 聂祝锋

    2011-01-01

    目的:调查不同类型整形医疗机构顾客特征、寻医行为特征及相关影响因素,提出顾客管理建议.方法:对公立三甲医院整形顾客74例、民营整形门诊顾客108例进行寻医行为现状调查,并于1个月后对其满意度进行追踪随访;利用t检验和卡方分析进行描述性分析和比较.结果:与民营整形机构相比,公立医院整形顾客年龄明显偏大,而经济水平等其他人口学特征差异不大;两组对象整形信息的获得渠道都以网络、电视、刊物等外围媒介为主,但在具体渠道构成上有差异.两组顾客事先都有咨询公立医疗机构的经历,但本次整形决策动因和选择机构的原因有差异.顾客术后满意度分别为81%和85%,1个月后随访满意度略有提高,两组间2次满意度差异不大,但公立医院顾客更满意医院技术水平,而民营整形机构顾客更满意的是民营机构的服务态度.结论:合理引导整形顾客的整形寻医行为,公立医疗机构须加大咨询的力度,两类医疗机构都须加强顾客管理,提高顾客满意度.%Objective: Investigate the customer plastic medical searching behavior, to explore customer' s characteristics, decision factors and customer management stategy of different plastic medicalinstitutions. Methods: A questionnaire survey was used in the study. 74 customers of public medical institution and 108 customers of private hospital underwent an investigation, and then follow-up survey was used. T-test and chisquare analysis was applied to comparison and descriptive. Results: Except age, there is no significant demographic difference between two groups; Plastic information acquirements of two groups are Internet, television and publication Customers have prior consultation in public medical institution, but the motive and the cause of selecting mechanisms on two groups have differences. Satisfaction of two groups is no difference, but public hospital plastic customers

  11. Evidence for phenotypic plasticity in aggressive triple-negative breast cancer: human biology is recapitulated by a novel model system.

    Directory of Open Access Journals (Sweden)

    Nicholas C D'Amato

    Full Text Available Breast cancers with a basal-like gene signature are primarily triple-negative, frequently metastatic, and carry a poor prognosis. Basal-like breast cancers are enriched for markers of breast cancer stem cells as well as markers of epithelial-mesenchymal transition (EMT. While EMT is generally thought to be important in the process of metastasis, in vivo evidence of EMT in human disease remains rare. Here we report a novel model of human triple-negative breast cancer, the DKAT cell line, which was isolated from an aggressive, treatment-resistant triple-negative breast cancer that demonstrated morphological and biochemical evidence suggestive of phenotypic plasticity in the patient. The DKAT cell line displays a basal-like phenotype in vitro when cultured in serum-free media, and undergoes phenotypic changes consistent with EMT/MET in response to serum-containing media, a unique property among the breast cancer cell lines we tested. This EMT is marked by increased expression of the transcription factor Zeb1, and Zeb1 is required for the enhanced migratory ability of DKAT cells in the mesenchymal state. DKAT cells also express progenitor-cell markers, and single DKAT cells are able to generate tumorspheres containing both epithelial and mesenchymal cell types. In vivo, as few as ten DKAT cells are capable of forming xenograft tumors which display a range of epithelial and mesenchymal phenotypes. The DKAT model provides a novel model to study the molecular mechanisms regulating phenotypic plasticity and the aggressive biology of triple-negative breast cancers.

  12. MUTZ-3 derived Langerhans cells in human skin equivalents show differential migration and phenotypic plasticity after allergen or irritant exposure.

    Science.gov (United States)

    Kosten, Ilona J; Spiekstra, Sander W; de Gruijl, Tanja D; Gibbs, Susan

    2015-08-15

    After allergen or irritant exposure, Langerhans cells (LC) undergo phenotypic changes and exit the epidermis. In this study we describe the unique ability of MUTZ-3 derived Langerhans cells (MUTZ-LC) to display similar phenotypic plasticity as their primary counterparts when incorporated into a physiologically relevant full-thickness skin equivalent model (SE-LC). We describe differences and similarities in the mechanisms regulating LC migration and plasticity upon allergen or irritant exposure. The skin equivalent consisted of a reconstructed epidermis containing primary differentiated keratinocytes and CD1a(+) MUTZ-LC on a primary fibroblast-populated dermis. Skin equivalents were exposed to a panel of allergens and irritants. Topical exposure to sub-toxic concentrations of allergens (nickel sulfate, resorcinol, cinnamaldehyde) and irritants (Triton X-100, SDS, Tween 80) resulted in LC migration out of the epidermis and into the dermis. Neutralizing antibody to CXCL12 blocked allergen-induced migration, whereas anti-CCL5 blocked irritant-induced migration. In contrast to allergen exposure, irritant exposure resulted in cells within the dermis becoming CD1a(-)/CD14(+)/CD68(+) which is characteristic of a phenotypic switch of MUTZ-LC to a macrophage-like cell in the dermis. This phenotypic switch was blocked with anti-IL-10. Mechanisms previously identified as being involved in LC activation and migration in native human skin could thus be reproduced in the in vitro constructed skin equivalent model containing functional LC. This model therefore provides a unique and relevant research tool to study human LC biology in situ under controlled in vitro conditions, and will provide a powerful tool for hazard identification, testing novel therapeutics and identifying new drug targets.

  13. Music-induced cortical plasticity and lateral inhibition in the human auditory cortex as foundations for tonal tinnitus treatment

    Science.gov (United States)

    Pantev, Christo; Okamoto, Hidehiko; Teismann, Henning

    2012-01-01

    Over the past 15 years, we have studied plasticity in the human auditory cortex by means of magnetoencephalography (MEG). Two main topics nurtured our curiosity: the effects of musical training on plasticity in the auditory system, and the effects of lateral inhibition. One of our plasticity studies found that listening to notched music for 3 h inhibited the neuronal activity in the auditory cortex that corresponded to the center-frequency of the notch, suggesting suppression of neural activity by lateral inhibition. Subsequent research on this topic found that suppression was notably dependent upon the notch width employed, that the lower notch-edge induced stronger attenuation of neural activity than the higher notch-edge, and that auditory focused attention strengthened the inhibitory networks. Crucially, the overall effects of lateral inhibition on human auditory cortical activity were stronger than the habituation effects. Based on these results we developed a novel treatment strategy for tonal tinnitus—tailor-made notched music training (TMNMT). By notching the music energy spectrum around the individual tinnitus frequency, we intended to attract lateral inhibition to auditory neurons involved in tinnitus perception. So far, the training strategy has been evaluated in two studies. The results of the initial long-term controlled study (12 months) supported the validity of the treatment concept: subjective tinnitus loudness and annoyance were significantly reduced after TMNMT but not when notching spared the tinnitus frequencies. Correspondingly, tinnitus-related auditory evoked fields (AEFs) were significantly reduced after training. The subsequent short-term (5 days) training study indicated that training was more effective in the case of tinnitus frequencies ≤ 8 kHz compared to tinnitus frequencies >8 kHz, and that training should be employed over a long-term in order to induce more persistent effects. Further development and evaluation of TMNMT therapy

  14. Edwin Grant Dexter: an early researcher in human behavioral biometeorology

    Science.gov (United States)

    Stewart, Alan E.

    2015-06-01

    Edwin Grant Dexter (1868-1938) was one of the first researchers to study empirically the effects of specific weather conditions on human behavior. Dexter (1904) published his findings in a book, Weather influences. The author's purposes in this article were to (1) describe briefly Dexter's professional life and examine the historical contexts and motivations that led Dexter to conduct some of the first empirical behavioral biometeorological studies of the time, (2) describe the methods Dexter used to examine weather-behavior relationships and briefly characterize the results that he reported in Weather influences, and (3) provide a historical analysis of Dexter's work and assess its significance for human behavioral biometeorology. Dexter's Weather influences, while demonstrating an exemplary approach to weather, health, and behavior relationships, came at the end of a long era of such studies, as health, social, and meteorological sciences were turning to different paradigms to advance their fields. For these reasons, Dexter's approach and contributions may not have been fully recognized at the time and are, consequently, worthy of consideration by contemporary biometeorologists.

  15. Human behavioral assessments in current research of Parkinson's disease.

    Science.gov (United States)

    Asakawa, Tetsuya; Fang, Huan; Sugiyama, Kenji; Nozaki, Takao; Kobayashi, Susumu; Hong, Zhen; Suzuki, Katsuaki; Mori, Norio; Yang, Yilin; Hua, Fei; Ding, Guanghong; Wen, Guoqiang; Namba, Hiroki; Xia, Ying

    2016-09-01

    Parkinson's disease (PD) is traditionally classified as a movement disorder because patients mainly complain about motor symptoms. Recently, non-motor symptoms of PD have been recognized by clinicians and scientists as early signs of PD, and they are detrimental factors in the quality of life in advanced PD patients. It is crucial to comprehensively understand the essence of behavioral assessments, from the simplest measurement of certain symptoms to complex neuropsychological tasks. We have recently reviewed behavioral assessments in PD research with animal models (Asakawa et al., 2016). As a companion volume, this article will systematically review the behavioral assessments of motor and non-motor PD symptoms of human patients in current research. The major aims of this article are: (1) promoting a comparative understanding of various behavioral assessments in terms of the principle and measuring indexes; (2) addressing the major strengths and weaknesses of these behavioral assessments for a better selection of tasks/tests in order to avoid biased conclusions due to inappropriate assessments; and (3) presenting new concepts regarding the development of wearable devices and mobile internet in future assessments. In conclusion we emphasize the importance of improving the assessments for non-motor symptoms because of their complex and unique mechanisms in human PD brains.

  16. Understanding the heavy-tailed dynamics in human behavior

    Science.gov (United States)

    Ross, Gordon J.; Jones, Tim

    2015-06-01

    The recent availability of electronic data sets containing large volumes of communication data has made it possible to study human behavior on a larger scale than ever before. From this, it has been discovered that across a diverse range of data sets, the interevent times between consecutive communication events obey heavy-tailed power law dynamics. Explaining this has proved controversial, and two distinct hypotheses have emerged. The first holds that these power laws are fundamental, and arise from the mechanisms such as priority queuing that humans use to schedule tasks. The second holds that they are statistical artifacts which only occur in aggregated data when features such as circadian rhythms and burstiness are ignored. We use a large social media data set to test these hypotheses, and find that although models that incorporate circadian rhythms and burstiness do explain part of the observed heavy tails, there is residual unexplained heavy-tail behavior which suggests a more fundamental cause. Based on this, we develop a quantitative model of human behavior which improves on existing approaches and gives insight into the mechanisms underlying human interactions.

  17. The Humanism of Rational Emotive Behavior Therapy and Other Cognitive Behavior Therapies.

    Science.gov (United States)

    Ellis, Albert

    1996-01-01

    Describes aspects of rational emotive behavior therapy (REBT). REBT shows how people can both create and uncreate many of their emotional disturbances. It is a theory of personality which avoids devotion to any kind of magic and supernaturalism and emphasizes unconditional self-acceptance, antiabsolutism, uncertainty, and human fallibility. (RJM)

  18. The Humanism of Rational Emotive Behavior Therapy and Other Cognitive Behavior Therapies.

    Science.gov (United States)

    Ellis, Albert

    1996-01-01

    Describes aspects of rational emotive behavior therapy (REBT). REBT shows how people can both create and uncreate many of their emotional disturbances. It is a theory of personality which avoids devotion to any kind of magic and supernaturalism and emphasizes unconditional self-acceptance, antiabsolutism, uncertainty, and human fallibility. (RJM)

  19. Developmental Plasticity and Language: A Comparative Perspective.

    Science.gov (United States)

    Griebel, Ulrike; Pepperberg, Irene M; Oller, D Kimbrough

    2016-04-01

    The growing field of evo-devo is increasingly demonstrating the complexity of steps involved in genetic, intracellular regulatory, and extracellular environmental control of the development of phenotypes. A key result of such work is an account for the remarkable plasticity of organismal form in many species based on relatively minor changes in regulation of highly conserved genes and genetic processes. Accounting for behavioral plasticity is of similar potential interest but has received far less attention. Of particular interest is plasticity in communication systems, where human language represents an ultimate target for research. The present paper considers plasticity of language capabilities in a comparative framework, focusing attention on examples of a remarkable fact: Whereas there exist design features of mature human language that have never been observed to occur in non-humans in the wild, many of these features can be developed to notable extents when non-humans are enculturated through human training (especially with intensive social interaction). These examples of enculturated developmental plasticity across extremely diverse taxa suggest, consistent with the evo-devo theme of highly conserved processes in evolution, that human language is founded in part on cognitive capabilities that are indeed ancient and that even modern humans show self-organized emergence of many language capabilities in the context of rich enculturation, built on the special social/ecological history of the hominin line. Human culture can thus be seen as a regulatory system encouraging language development in the context of a cognitive background with many highly conserved features. Copyright © 2016 Cognitive Science Society, Inc.

  20. Chaos in human behavior: the case of work motivation.

    Science.gov (United States)

    Navarro, José; Arrieta, Carlos

    2010-05-01

    This study considers the complex dynamics of work motivation. Forty-eight employees completed a work-motivation diary several times per day over a period of four weeks. The obtained time series were analysed using different methodologies derived from chaos theory (i.e. recurrence plots, Lyapunov exponents, correlation dimension and surrogate data). Results showed chaotic dynamics in 75% of cases. The findings confirm the universality of chaotic behavior within human behavior, challenge some of the underlying assumptions on which work motivation theories are based, and suggest that chaos theory may offer useful and relevant information on how this process is managed within organizations.

  1. Discrimination of complex human behavior by pigeons (Columba livia and humans.

    Directory of Open Access Journals (Sweden)

    Muhammad A J Qadri

    Full Text Available The cognitive and neural mechanisms for recognizing and categorizing behavior are not well understood in non-human animals. In the current experiments, pigeons and humans learned to categorize two non-repeating, complex human behaviors ("martial arts" vs. "Indian dance". Using multiple video exemplars of a digital human model, pigeons discriminated these behaviors in a go/no-go task and humans in a choice task. Experiment 1 found that pigeons already experienced with discriminating the locomotive actions of digital animals acquired the discrimination more rapidly when action information was available than when only pose information was available. Experiments 2 and 3 found this same dynamic superiority effect with naïve pigeons and human participants. Both species used the same combination of immediately available static pose information and more slowly perceived dynamic action cues to discriminate the behavioral categories. Theories based on generalized visual mechanisms, as opposed to embodied, species-specific action networks, offer a parsimonious account of how these different animals recognize behavior across and within species.

  2. Behavioral responses associated with a human-mediated predator shelter.

    Directory of Open Access Journals (Sweden)

    Graeme Shannon

    Full Text Available Human activities in protected areas can affect wildlife populations in a similar manner to predation risk, causing increases in movement and vigilance, shifts in habitat use and changes in group size. Nevertheless, recent evidence indicates that in certain situations ungulate species may actually utilize areas associated with higher levels of human presence as a potential refuge from disturbance-sensitive predators. We now use four-years of behavioral activity budget data collected from pronghorn (Antilocapra americana and elk (Cervus elephus in Grand Teton National Park, USA to test whether predictable patterns of human presence can provide a shelter from predatory risk. Daily behavioral scans were conducted along two parallel sections of road that differed in traffic volume--with the main Teton Park Road experiencing vehicle use that was approximately thirty-fold greater than the River Road. At the busier Teton Park Road, both species of ungulate engaged in higher levels of feeding (27% increase in the proportion of pronghorn feeding and 21% increase for elk, lower levels of alert behavior (18% decrease for pronghorn and 9% decrease for elk and formed smaller groups. These responses are commonly associated with reduced predatory threat. Pronghorn also exhibited a 30% increase in the proportion of individuals moving at the River Road as would be expected under greater exposure to predation risk. Our findings concur with the 'predator shelter hypothesis', suggesting that ungulates in GTNP use human presence as a potential refuge from predation risk, adjusting their behavior accordingly. Human activity has the potential to alter predator-prey interactions and drive trophic-mediated effects that could ultimately impact ecosystem function and biodiversity.

  3. Neuronal plasticity after a human spinal cord injury: positive and negative effects.

    Science.gov (United States)

    Dietz, Volker

    2012-05-01

    In patients suffering an incomplete spinal cord injury (SCI) an improvement in walking function can be achieved by providing a functional training with an appropriate afferent input. In contrast, in immobilized incomplete and complete subjects a negative neuroplasticity leads to a neuronal dysfunction. After an SCI, neuronal centers below the level of lesion exhibit plasticity that either can be exploited by specific training paradigms or undergo a degradation of function due to the loss of appropriate input. Load- and hip-joint-related afferent inputs seem to be of crucial importance for the generation of a locomotor pattern and, consequently, the effectiveness of the locomotor training. In severely affected SCI subjects rehabilitation robots allow for a longer and more intensive training and can provide feedback information. Conversely, in severely affected chronic SCI individuals without functional training the locomotor activity in the leg muscles exhausts rapidly during assisted locomotion. This is accompanied by a shift from early to dominant late spinal reflex components. The exhaustion of locomotor activity is also observed in non-ambulatory patients with an incomplete SCI. It is assumed that in chronic SCI the patient's immobility results in a reduced input from supraspinal and peripheral sources and leads to a dominance of inhibitory drive within spinal neuronal circuitries underlying locomotor pattern and spinal reflex generation. A training with an enhancement of an appropriate proprioceptive input early after an SCI might serve as an intervention to prevent neuronal dysfunction.

  4. Accommodating complexity and human behaviors in decision analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Siirola, John Daniel; Schoenwald, David Alan; Strip, David R.; Hirsch, Gary B.; Bastian, Mark S.; Braithwaite, Karl R.; Homer, Jack [Homer Consulting

    2007-11-01

    This is the final report for a LDRD effort to address human behavior in decision support systems. One sister LDRD effort reports the extension of this work to include actual human choices and additional simulation analyses. Another provides the background for this effort and the programmatic directions for future work. This specific effort considered the feasibility of five aspects of model development required for analysis viability. To avoid the use of classified information, healthcare decisions and the system embedding them became the illustrative example for assessment.

  5. Sensitivity analysis techniques for models of human behavior.

    Energy Technology Data Exchange (ETDEWEB)

    Bier, Asmeret Brooke

    2010-09-01

    Human and social modeling has emerged as an important research area at Sandia National Laboratories due to its potential to improve national defense-related decision-making in the presence of uncertainty. To learn about which sensitivity analysis techniques are most suitable for models of human behavior, different promising methods were applied to an example model, tested, and compared. The example model simulates cognitive, behavioral, and social processes and interactions, and involves substantial nonlinearity, uncertainty, and variability. Results showed that some sensitivity analysis methods create similar results, and can thus be considered redundant. However, other methods, such as global methods that consider interactions between inputs, can generate insight not gained from traditional methods.

  6. Understanding the Heavy Tailed Dynamics in Human Behavior

    CERN Document Server

    Ross, Gordon J

    2015-01-01

    The recent availability of electronic datasets containing large volumes of communication data has made it possible to study human behavior on a larger scale than ever before. From this, it has been discovered that across a diverse range of data sets, the inter-event times between consecutive communication events obey heavy tailed power law dynamics. Explaining this has proved controversial, and two distinct hypotheses have emerged. The first holds that these power laws are fundamental, and arise from the mechanisms such as priority queuing that humans use to schedule tasks. The second holds that they are a statistical artifact which only occur in aggregated data when features such as circadian rhythms and burstiness are ignored. We use a large social media data set to test these hypotheses, and find that although models that incorporate circadian rhythms and burstiness do explain part of the observed heavy tails, there is residual unexplained heavy tail behavior which suggests a more fundamental cause. Based ...

  7. Arginine vasopressin and oxytocin modulate human social behavior.

    Science.gov (United States)

    Ebstein, Richard P; Israel, Salomon; Lerer, Elad; Uzefovsky, Florina; Shalev, Idan; Gritsenko, Inga; Riebold, Mathias; Salomon, Shahaf; Yirmiya, Nurit

    2009-06-01

    Increasing evidence suggests that two nonapeptides, arginine vasopressin and oxytocin, shape human social behavior in both nonclinical and clinical subjects. Evidence is discussed that in autism spectrum disorders genetic polymorphisms in the vasopressin-oxytocin pathway, notably the arginine vasopressin receptor 1a (AVPR1a), the oxytocin receptor (OXTR), neurophysin I and II, and CD38 (recently shown to be critical for social behavior by mediating oxytocin secretion) contribute to deficits in socialization skills in this group of patients. We also present first evidence that CD38 expression in lymphoblastoid cells derived from subjects diagnosed with autism is correlated with social skill phenotype inventoried by the Vineland Adaptive Behavioral Scales. Additionally, we discuss molecular genetic evidence that in nonclinical subjects both AVPR1a and OXTR genes contribute to prosocial or altruistic behavior inventoried by two experimental paradigms, the dictator game and social values orientation. The role of the AVPR1a is also analyzed in prepulse inhibition. Prepulse inhibition of the startle response to auditory stimuli is a largely autonomic response that resonates with social cognition in both animal models and humans. First results are presented showing that intranasal administration of arginine vasopressin increases salivary cortisol levels in the Trier Social Stress test. To summarize, accumulating studies employing a broad array of cutting-edge tools in psychology, neuroeconomics, molecular genetics, pharmacology, electrophysiology, and brain imaging are beginning to elaborate the intriguing role of oxytocin and arginine vasopressin in human social behavior. We expect that future studies will continue this advance and deepen our understanding of these complex events.

  8. Learning dynamics explains human behavior in Prisoner's Dilemma on networks

    CERN Document Server

    Cimini, Giulio

    2014-01-01

    Cooperative behavior lies at the very basis of human societies, yet its evolutionary origin remains a key unsolved puzzle. Whereas reciprocity or conditional cooperation is one of the most prominent mechanisms proposed to explain the emergence of cooperation in social dilemmas, recent experimental findings on networked Prisoner's Dilemma games suggest that conditional cooperation also depends on the previous action of the player---namely on the `mood' in which the player currently is. Roughly, a majority of people behaves as conditional cooperators if they cooperated in the past, while they ignore the context and free-ride with high probability if they did not. However, the ultimate origin of this behavior represents a conundrum itself. Here we aim specifically at providing an evolutionary explanation of moody conditional cooperation. To this end, we perform an extensive analysis of different evolutionary dynamics for players' behavioral traits---ranging from standard processes used in game theory based on pa...

  9. Investigation of Mechanical Properties and Plastic Deformation Behavior of (Ti45Cu40Zr10Ni5100−xAlx Metallic Glasses by Nanoindentation

    Directory of Open Access Journals (Sweden)

    Lanping Huang

    2014-01-01

    Full Text Available The effect of Al addition on mechanical properties and plastic deformation behavior of (Ti45Cu40Zr10Ni5100−xAlx (x = 0, 2, 4, 6 and 8 amorphous alloy ribbons have been investigated by nanoindentation. The hardness and elastic modulus do not simply increase with the increase of Al content. The alloy with 8 at.% Al exhibits the highest hardness and elastic modulus. The serrations or pop-in events are strongly dependent on the loading rate and alloy composition.

  10. Reassembling the Social Environment: A Network Approack to Human Behavior

    OpenAIRE

    Dhrubodhi Mukherjee

    2007-01-01

    This paper critically examines the influence of the structural elements of human behavior that are often neglected in social work literature (Robbins et al., 1998). It incorporates a new multi-theoretical framework that critically examines the significance of a network approach in analyzing social, ideological, and economic structures and their influence on individual actors. This paper discusses two interrelated theories: social network theory and social capital theory, and critiques their r...

  11. Health, Human Capital, and Behavior Change: Essays in Development Microeconomics

    OpenAIRE

    Kirk, Angeli Elise

    2016-01-01

    This dissertation combines three empirical studies of household behaviors as they relate to investment in health and human capital in developing countries. The first explores how changes in children's nutrition in Uganda correspond to composition of a household's income. The second studies measurement activities in a cookstove intervention in Darfur, Sudan, with insights into what may be missed in traditional evaluation approaches as well as how technology adoption may benefit from an uninten...

  12. Some theoretical aspects of human categorization behavior: similarity and generalization

    OpenAIRE

    Jäkel, Frank

    2007-01-01

    Explanations of human categorization behavior often invoke similarity. Stimuli that are similar to each other are grouped together whereas stimuli that are very different are kept separate. Despite serious problems in defining similarity, both conceptually and experimentally, this is the prevailing view of categorization in prototype models (Posner & Keele, 1968; Reed, 1972) and exemplar models (Medin & Schaffer, 1978; Nosofsky, 1986). This is also the prevailing approach in machine learning ...

  13. Microstructure and High Temperature Plastic Deformation Behavior of Al-12Si Based Alloy Fabricated by an Electromagnetic Casting and Stirring Process

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Kyung-Soo; Roh, Heung-Ryeol; Kim, Mok-Soon [Inha University, Incheon (Korea, Republic of); Kim, Jong-Ho; Park, Joon-Pyo [Research Institute of Industrial Science and Technology, Pohang (Korea, Republic of)

    2017-06-15

    An as-received EMC/S (electromagnetic casting and stirring)-processed Al-12Si based alloy billet was homogenized to examine its microstructure and high temperature plastic deformation behavior, using compressive tests over the temperature range from 623 to 743 K and a strain rate range from 1.0×10{sup -3} to 1.0×10{sup 0}s{sup -1}. The results were compared with samples processed by the direct chill casting (DC) method. The fraction of equiaxed structure for the as-received EMC/S billet(41%) was much higher than that of the as-received DC billet(6 %). All true stress – true strain curves acquired from the compressive tests exhibited a peak stress at the initial stage of plastic deformation. Flow stress showed a steady state region after the appearance of peak stress with increasing strain. The peak stress decreased with increasing temperature at a given strain rate and a decreasing strain rate at a given temperature. A constitutive equation was made for each alloy, which could be used to predict the peak stress. A recrystallized grain structure was observed in all the deformed specimens, indicating that dynamic recrystallization is the predominant mechanism during high temperature plastic deformation of both the homogenized EMC/S and DC-processed Al-12Si based alloys.

  14. Plastic Jellyfish.

    Science.gov (United States)

    Moseley, Christine

    2000-01-01

    Presents an environmental science activity designed to enhance students' awareness of the hazards of plastic waste for wildlife in aquatic environments. Discusses how students can take steps to reduce the effects of plastic waste. (WRM)

  15. Human handling promotes compliant behavior in adult laboratory rabbits.

    Science.gov (United States)

    Swennes, Alton G; Alworth, Leanne C; Harvey, Stephen B; Jones, Carolyn A; King, Christopher S; Crowell-Davis, Sharon L

    2011-01-01

    Routine laboratory procedures can be stressful for laboratory animals. We wanted to determine whether human handling of adult rabbits could induce a degree of habituation, reducing stress and facilitating research-related manipulation. To this end, adult New Zealand white rabbits were handled either frequently or minimally. After being handled over 3 wk, these rabbits were evaluated by novel personnel and compared with minimally handled controls. Evaluators subjectively scored the rabbits for their relative compliance or resistance to being scruffed and removed from their cages, being transported to a treatment room, and their behavior at all stages of the exercise. Upon evaluation, handled rabbits scored significantly more compliant than nontreated controls. During evaluation, behaviors that the rabbits displayed when they were approached in their cages and while being handled outside their cages were recorded and compared between study groups. Handled rabbits displayed behavior consistent with a reduction in human-directed fear. This study illustrates the potential for handling to improve compliance in laboratory procedures and reduce fear-related behavior in laboratory rabbits. Such handling could be used to improve rabbit welfare through the reduction of stress and exposure to novel stimuli.

  16. Training together: how another human's presence affects behavior during virtual human-based team training

    Directory of Open Access Journals (Sweden)

    Andrew Robb

    2016-08-01

    Full Text Available Despite research showing that team training can lead to strong improvements in team performance, logistical difficulties can prevent team training programs from being adopted on a large scale. A proposed solution to these difficulties is the use of virtual humans to replace missing teammates. Existing research evaluating the use of virtual humans for team training has been conducted in settings involving a single human trainee. However, in the real world multiple human trainees would most likely train together. In this paper, we explore how the presence of a second human trainee can alter behavior during a medical team training program. Ninety-two nurses and surgical technicians participated in a medical training exercise, where they worked with a virtual surgeon and virtual anesthesiologist to prepare a simulated patient for surgery. The agency of the nurse and the surgical technician were varied between three conditions: human nurses and surgical technicians working together; human nurses working with a virtual surgical technician; and human surgical technicians working with a virtual nurse. Variations in agency did not produce statistically significant differences in the training outcomes, but several notable differences were observed in other aspects of the team's behavior. Specifically, when working with a virtual nurse, human surgical technicians were more likely to assist with speaking up about patient safety issues that were outside of their normal responsibilities; human trainees spent less time searching for a missing item when working with a virtual partner, likely because the virtual partner was physically unable to move throughout the room and assist with the searching process; and more breaks in presence were observed when two human teammates were present. These results show that some behaviors may be influenced by the presence of multiple human trainees, though these behaviors may not impinge on core training goals. When

  17. Human behavior recognition using a context-free grammar

    Science.gov (United States)

    Rosani, Andrea; Conci, Nicola; De Natale, Francesco G. B.

    2014-05-01

    Automatic recognition of human activities and behaviors is still a challenging problem for many reasons, including limited accuracy of the data acquired by sensing devices, high variability of human behaviors, and gap between visual appearance and scene semantics. Symbolic approaches can significantly simplify the analysis and turn raw data into chains of meaningful patterns. This allows getting rid of most of the clutter produced by low-level processing operations, embedding significant contextual information into the data, as well as using simple syntactic approaches to perform the matching between incoming sequences and models. We propose a symbolic approach to learn and detect complex activities through the sequences of atomic actions. Compared to previous methods based on context-free grammars, we introduce several important novelties, such as the capability to learn actions based on both positive and negative samples, the possibility of efficiently retraining the system in the presence of misclassified or unrecognized events, and the use of a parsing procedure that allows correct detection of the activities also when they are concatenated and/or nested one with each other. An experimental validation on three datasets with different characteristics demonstrates the robustness of the approach in classifying complex human behaviors.

  18. The human factor: behavioral and neural correlates of humanized perception in moral decision making.

    Directory of Open Access Journals (Sweden)

    Jasminka Majdandžić

    Full Text Available The extent to which people regard others as full-blown individuals with mental states ("humanization" seems crucial for their prosocial motivation towards them. Previous research has shown that decisions about moral dilemmas in which one person can be sacrificed to save multiple others do not consistently follow utilitarian principles. We hypothesized that this behavior can be explained by the potential victim's perceived humanness and an ensuing increase in vicarious emotions and emotional conflict during decision making. Using fMRI, we assessed neural activity underlying moral decisions that affected fictitious persons that had or had not been experimentally humanized. In implicit priming trials, participants either engaged in mentalizing about these persons (Humanized condition or not (Neutral condition. In subsequent moral dilemmas, participants had to decide about sacrificing these persons' lives in order to save the lives of numerous others. Humanized persons were sacrificed less often, and the activation pattern during decisions about them indicated increased negative affect, emotional conflict, vicarious emotions, and behavioral control (pgACC/mOFC, anterior insula/IFG, aMCC and precuneus/PCC. Besides, we found enhanced effective connectivity between aMCC and anterior insula, which suggests increased emotion regulation during decisions affecting humanized victims. These findings highlight the importance of others' perceived humanness for prosocial behavior - with aversive affect and other-related concern when imagining harming more "human-like" persons acting against purely utilitarian decisions.

  19. Age-related changes in the plasticity and toughness of human cortical bone at multiple length-scales

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Elizabeth A.; Schaible, Eric; Bale, Hrishikesh; Barth, Holly D.; Tang, Simon Y.; Reichert, Peter; Busse, Bjoern; Alliston, Tamara; Ager III, Joel W.; Ritchie, Robert O.

    2011-08-10

    The structure of human cortical bone evolves over multiple length-scales from its basic constituents of collagen and hydroxyapatite at the nanoscale to osteonal structures at nearmillimeter dimensions, which all provide the basis for its mechanical properties. To resist fracture, bone’s toughness is derived intrinsically through plasticity (e.g., fibrillar sliding) at structural-scales typically below a micron and extrinsically (i.e., during crack growth) through mechanisms (e.g., crack deflection/bridging) generated at larger structural-scales. Biological factors such as aging lead to a markedly increased fracture risk, which is often associated with an age-related loss in bone mass (bone quantity). However, we find that age-related structural changes can significantly degrade the fracture resistance (bone quality) over multiple lengthscales. Using in situ small-/wide-angle x-ray scattering/diffraction to characterize sub-micron structural changes and synchrotron x-ray computed tomography and in situ fracture-toughness measurements in the scanning electron microscope to characterize effects at micron-scales, we show how these age-related structural changes at differing size-scales degrade both the intrinsic and extrinsic toughness of bone. Specifically, we attribute the loss in toughness to increased non-enzymatic collagen cross-linking which suppresses plasticity at nanoscale dimensions and to an increased osteonal density which limits the potency of crack-bridging mechanisms at micron-scales. The link between these processes is that the increased stiffness of the cross-linked collagen requires energy to be absorbed by “plastic” deformation at higher structural levels, which occurs by the process of microcracking.

  20. Associative plasticity in the human motor cortex is enhanced by concurrently targeting separate muscle representations with excitatory and inhibitory protocols.

    Science.gov (United States)

    Kamke, Marc R; Nydam, Abbey S; Sale, Martin V; Mattingley, Jason B

    2016-04-01

    Paired associative stimulation (PAS) induces changes in the excitability of human sensorimotor cortex that outlast the procedure. PAS typically involves repeatedly pairing stimulation of a peripheral nerve that innervates an intrinsic hand muscle with transcranial magnetic stimulation over the representation of that muscle in the primary motor cortex. Depending on the timing of the stimuli (interstimulus interval of 25 or 10 ms), PAS leads to either an increase (PAS25) or a decrease (PAS10) in excitability. Both protocols, however, have been associated with an increase in excitability of nearby muscle representations not specifically targeted by PAS. Based on these spillover effects, we hypothesized that an additive, excitability-enhancing effect of PAS25 applied to one muscle representation may be produced by simultaneously applying PAS25 or PAS10 to a nearby representation. In different experiments prototypical PAS25 targeting the left thumb representation [abductor pollicis brevis (APB)] was combined with either PAS25 or PAS10 applied to the left little finger representation [abductor digiti minimi (ADM)] or, in a control experiment, with PAS10 also targeting the APB. In an additional control experiment PAS10 targeted both representations. The plasticity effects were quantified by measuring the amplitude of motor evoked potentials (MEPs) recorded before and after PAS. As expected, prototypical PAS25 was associated with an increase in MEP amplitude in the APB muscle. This effect was enhanced when PAS also targeted the ADM representation but only when a different interstimulus timing (PAS10) was used. These results suggest that PAS-induced plasticity is modified by concurrently targeting separate motor cortical representations with excitatory and inhibitory protocols.

  1. Regulation of hippocampal synaptic plasticity thresholds and changes in exploratory and learning behavior in dominant negative NPR-B mutant rats

    Science.gov (United States)

    Barmashenko, Gleb; Buttgereit, Jens; Herring, Neil; Bader, Michael; Özcelik, Cemil; Manahan-Vaughan, Denise; Braunewell, Karl H.

    2014-01-01

    The second messenger cyclic GMP affects synaptic transmission and modulates synaptic plasticity and certain types of learning and memory processes. The impact of the natriuretic peptide receptor B (NPR-B) and its ligand C-type natriuretic peptide (CNP), one of several cGMP producing signaling systems, on hippocampal synaptic plasticity and learning is, however, less well understood. We have previously shown that the NPR-B ligand CNP increases the magnitude of long-term depression (LTD) in hippocampal area CA1, while reducing the induction of long-term potentiation (LTP). We have extended this line of research to show that bidirectional plasticity is affected in the opposite way in rats expressing a dominant-negative mutant of NPR-B (NSE-NPR-BΔKC) lacking the intracellular guanylyl cyclase domain under control of a promoter for neuron-specific enolase. The brain cells of these transgenic rats express functional dimers of the NPR-B receptor containing the dominant-negative NPR-BΔKC mutant, and therefore show decreased CNP-stimulated cGMP-production in brain membranes. The NPR-B transgenic rats display enhanced LTP but reduced LTD in hippocampal slices. When the frequency-dependence of synaptic modification to afferent stimulation in the range of 1–100 Hz was assessed in transgenic rats, the threshold for both, LTP and LTD induction, was shifted to lower frequencies. In parallel, NPR-BΔKC rats exhibited an enhancement in exploratory and learning behavior. These results indicate that bidirectional plasticity and learning and memory mechanism are affected in transgenic rats expressing a dominant-negative mutant of NPR-B. Our data substantiate the hypothesis that NPR-B-dependent cGMP signaling has a modulatory role for synaptic information storage and learning. PMID:25520616

  2. Regulation of hippocampal synaptic plasticity thresholds and changes in exploratory and learning behavior in dominant negative NPR-B mutant rats

    Directory of Open Access Journals (Sweden)

    Gleb eBarmashenko

    2014-12-01

    Full Text Available The second messenger cyclic GMP affects synaptic transmission and modulates synaptic plasticity and certain types of learning and memory processes. The impact of the natriuretic peptide receptor B (NPR-B and its ligand C-type natriuretic peptide (CNP, one of several cGMP producing signalling systems, on hippocampal synaptic plasticity and learning is, however, less well understood. We have previously shown that the NPR-B ligand CNP increases the magnitude of long-term depression (LTD in hippocampal area CA1, while reducing the induction of long-term potentiation (LTP. We have extended this line of research to show that bidirectional plasticity is affected in the opposite way in rats expressing a dominant-negative mutant of NPR-B (NSE-NPR-BdeltaKC lacking the intracellular guanylyl cyclase domain under control of a promoter for neuron-specific enolase. The brain cells of these transgenic rats express functional dimers of the NPR-B receptor containing the dominant-negative NPR-BdeltaKC mutant, and therefore show decreased CNP-stimulated cGMP-production in brain membranes. The NPR-B transgenic rats display enhanced LTP but reduced LTD in hippocampal slices. When the frequency-dependence of synaptic modification to afferent stimulation in the range of 1-100 Hz was assessed in transgenic rats the threshold for LTP induction was raised, but LTD induction was facilitated. In parallel, NPR-BdeltaKC rats exhibited an enhancement in exploratory and learning behavior. These results indicate that bidirectional plasticity and learning and memory mechanism are affected in transgenic rats expressing a dominant-negative mutant of NPR-B. Our data substantiate the hypothesis that NPR-B-dependent cGMP signalling has a modulatory role for synaptic information storage and learning.

  3. Discriminating Drivers through Human Factor and Behavioral Difference

    Directory of Open Access Journals (Sweden)

    Ju Seok Oh

    2011-05-01

    Full Text Available Since Greenwood and Woods' (1919 study in tendency of accident, many researchers have insisted that various human factors (sensation seeking, anger, anxiety are highly correlated with reckless driving and traffic accidents. Oh and Lee (2011 designed the Driving Behavior Determinants Questionnaire, a psychological tool to predict danger level of drivers and discriminate them into three groups (normal, unintentionally reckless, and intentionally reckless by their characteristics, attitude, and expected reckless behavior level. This tool's overall accuracy of discrimination was 70%. This study aimed to prove that the discrimination reflects the behavioral difference of drivers. Twenty-four young drivers were requested to react to the visual stimuli (tests for subjective speed sense, simple visual reaction time, and left turning at own risk. The results showed no differences in subjective speed sense among the driver groups, which means drivers' excessive speeding behaviors occur due to intention based on personality and attitude, not because of sensory disorders. In addition, there were no differences in simple reaction time among driver groups. However, the results of the ‘Left turning at drivers’ own risk task” revealed significant group differences. All reckless drivers showed a greater degree of dangerous left turning behaviors than the normal group did.

  4. On the effect of x-ray irradiation on the deformation and fracture behavior of human cortical bone

    Energy Technology Data Exchange (ETDEWEB)

    Barth, Holly D.; Launey, Maximilien E.; McDowell, Alastair A.; Ager III, Joel W.; Ritchie, Robert O.

    2010-01-10

    In situ mechanical testing coupled with imaging using high-energy synchrotron x-ray diffraction or tomography imaging is gaining in popularity as a technique to investigate micrometer and even sub-micrometer deformation and fracture mechanisms in mineralized tissues, such as bone and teeth. However, the role of the irradiation in affecting the nature and properties of the tissue is not always taken into account. Accordingly, we examine here the effect of x-ray synchrotron-source irradiation on the mechanistic aspects of deformation and fracture in human cortical bone. Specifically, the strength, ductility and fracture resistance (both work-of-fracture and resistance-curve fracture toughness) of human femoral bone in the transverse (breaking) orientation were evaluated following exposures to 0.05, 70, 210 and 630 kGy irradiation. Our results show that the radiation typically used in tomography imaging can have a major and deleterious impact on the strength, post-yield behavior and fracture toughness of cortical bone, with the severity of the effect progressively increasing with higher doses of radiation. Plasticity was essentially suppressed after as little as 70 kGy of radiation; the fracture toughness was decreased by a factor of five after 210 kGy of radiation. Mechanistically, the irradiation was found to alter the salient toughening mechanisms, manifest by the progressive elimination of the bone's capacity for plastic deformation which restricts the intrinsic toughening from the formation 'plastic zones' around crack-like defects. Deep-ultraviolet Raman spectroscopy indicated that this behavior could be related to degradation in the collagen integrity.

  5. Th17 plasticity in human autoimmune arthritis is driven by the inflammatory environment

    NARCIS (Netherlands)

    Nistala, Kiran; Adams, Stuart; Cambrook, Helen; Ursu, Simona; Olivito, Biagio; de Jager, Wilco; Evans, Jamie G.; Cimaz, Rolando; Bajaj-Elliott, Mona; Wedderburn, Lucy R.

    2010-01-01

    In several murine models of autoimmune arthritis, Th17 cells are the dominant initiators of inflammation. In human arthritis the majority of IL-17-secreting cells within the joint express a cytokine phenotype intermediate between Th17 and Th1. Here we show that Th17/1 cells from the joints of childr

  6. Plasticity of adult human pancreatic duct cells by neurogenin3-mediated reprogramming

    DEFF Research Database (Denmark)

    Swales, Nathalie; Martens, Geert A; Bonné, Stefan

    2012-01-01

    Duct cells isolated from adult human pancreas can be reprogrammed to express islet beta cell genes by adenoviral transduction of the developmental transcription factor neurogenin3 (Ngn3). In this study we aimed to fully characterize the extent of this reprogramming and intended to improve it....

  7. Cardiosphere conditioned media influence the plasticity of human mediastinal adipose tissue-derived mesenchymal stem cells.

    Science.gov (United States)

    Siciliano, Camilla; Chimenti, Isotta; Ibrahim, Mohsen; Napoletano, Chiara; Mangino, Giorgio; Scafetta, Gaia; Zoccai, Giuseppe Biondi; Rendina, Erino Angelo; Calogero, Antonella; Frati, Giacomo; De Falco, Elena

    2015-01-01

    Nowadays, cardiac regenerative medicine is facing many limitations because of the complexity to find the most suitable stem cell source and to understand the regenerative mechanisms involved. Mesenchymal stem cells (MSCs) have shown great regenerative potential due to their intrinsic properties and ability to restore cardiac functionality, directly by transdifferentiation and indirectly by paracrine effects. Yet, how MSCs could respond to definite cardiac-committing microenvironments, such as that created by resident cardiac progenitor cells in the form of cardiospheres (CSs), has never been addressed. Recently, a putative MSC pool has been described in the mediastinal fat (hmADMSCs), but both its biology and function remain hitherto unexplored. Accordingly, we investigated the potential of hmADMSCs to be committed toward a cardiovascular lineage after preconditioning with CS-conditioned media (CCM). Results indicated that CCM affects cell proliferation. Gene expression levels of multiple cardiovascular and stemness markers (MHC, KDR, Nkx2.5, Thy-1, c-kit, SMA) are significantly modulated, and the percentage of hmADMSCs preconditioned with CCM and positive for Nkx2.5, MHC, and KDR is significantly higher relative to FBS and explant-derived cell conditioned media (EDCM, the unselected stage before CS formation). Growth factor-specific and survival signaling pathways (i.e., Erk1/2, Akt, p38, mTOR, p53) present in CCM are all equally regulated. Nonetheless, earlier BAD phosphorylation (Ser112) occurs associated with the CS microenvironment (and to a lesser extent to EDCM), whereas faster phosphorylation of PRAS40 in FBS, and of Akt (Ser473) in EDCM and 5-azacytidine occurs compared to CCM. For the first time, we demonstrated that the MSC pool held in the mediastinal fat is adequately plastic to partially differentiate in vitro toward a cardiac-like lineage. Besides, we have provided novel evidence of the potent inductive niche-like microenvironment that the CS

  8. Human motion behavior while interacting with an industrial robot.

    Science.gov (United States)

    Bortot, Dino; Ding, Hao; Antonopolous, Alexandros; Bengler, Klaus

    2012-01-01

    Human workers and industrial robots both have specific strengths within industrial production. Advantageously they complement each other perfectly, which leads to the development of human-robot interaction (HRI) applications. Bringing humans and robots together in the same workspace may lead to potential collisions. The avoidance of such is a central safety requirement. It can be realized with sundry sensor systems, all of them decelerating the robot when the distance to the human decreases alarmingly and applying the emergency stop, when the distance becomes too small. As a consequence, the efficiency of the overall systems suffers, because the robot has high idle times. Optimized path planning algorithms have to be developed to avoid that. The following study investigates human motion behavior in the proximity of an industrial robot. Three different kinds of encounters between the two entities under three robot speed levels are prompted. A motion tracking system is used to capture the motions. Results show, that humans keep an average distance of about 0,5m to the robot, when the encounter occurs. Approximation of the workbenches is influenced by the robot in ten of 15 cases. Furthermore, an increase of participants' walking velocity with higher robot velocities is observed.

  9. Following Human Footsteps: Proposal of a Decision Theory Based on Human Behavior

    Science.gov (United States)

    Mahmud, Faisal

    2011-01-01

    Human behavior is a complex nature which depends on circumstances and decisions varying from time to time as well as place to place. The way a decision is made either directly or indirectly related to the availability of the options. These options though appear at random nature, have a solid directional way for decision making. In this paper, a decision theory is proposed which is based on human behavior. The theory is structured with model sets that will show the all possible combinations for making a decision, A virtual and simulated environment is considered to show the results of the proposed decision theory

  10. Thermal behavior of vehicle plastic blends contained acrylonitrile-butadiene-styrene (ABS) in pyrolysis using TG-FTIR.

    Science.gov (United States)

    Liu, Guicai; Liao, Yanfen; Ma, Xiaoqian

    2017-03-01

    As important plastic blends in End-of-Life vehicles (ELV), pyrolysis profiles of ABS/PVC, ABS/PA6 and ABS/PC were investigated using thermogravimetric-Fourier transform infrared spectrometer (TG-FTIR). Also, CaCO3 was added as plastic filler to discuss its effects on the pyrolysis of these plastics. The results showed that the interaction between ABS and PVC made PVC pyrolysis earlier and HCl emission slightly accelerated. The mixing of ABS and PA6 made their decomposition temperature closer, and ketones in PA6 pyrolysis products were reduced. The presence of ABS made PC pyrolysis earlier, and phenyl compounds in PC pyrolysis products could be transferred into alcohol or H2O. The interaction between ABS and other polymers in pyrolysis could be attributed to the intermolecular radical transfer, and free radicals from the polymer firstly decomposed led to a fast initiation the decomposition of the other polymer. As plastic filler, CaCO3 promoted the thermal decomposition of PA6 and PC, and had no obvious effects on ABS and PVC pyrolysis process. Also, CaCO3 made the pyrolysis products from PA6 and PC further decomposed into small-molecule compounds like CO2. The kinetics analysis showed that isoconversional method like Starink method was more suitable for these polymer blends. Starink method showed the average activation energy of ABS50/PVC50, ABS50/PA50 and ABS50/PC50 was 186.63kJ/mol, 239.61kJ/mol and 248.95kJ/mol, respectively, and the interaction among them could be reflected by the activation energy variation.

  11. Plasticity in mitochondrial cristae density allows metabolic capacity modulation in human skeletal muscle

    DEFF Research Database (Denmark)

    Nielsen, Joachim; Gejl, Kasper D; Hey-Mogensen, Martin;

    2016-01-01

    that this mechanism allows evasion of the trade-off between cell occupancy by mitochondria and other cellular constituents and improved metabolic capacity and fuel catabolism during prolonged elevated energy requirements. This article is protected by copyright. All rights reserved.......-body level, muscle mitochondrial cristae density is a better predictor of maximal oxygen uptake rate than muscle mitochondrial volume. Our findings establish elevating mitochondrial cristae density as a regulatory mechanism for increasing metabolic power in human skeletal muscle. We propose...

  12. Structural plasticity in the human cytosolic sulfotransferase dimer and its role in substrate selectivity and catalysis.

    Science.gov (United States)

    Tibbs, Zachary E; Rohn-Glowacki, Katie Jo; Crittenden, Frank; Guidry, Amber L; Falany, Charles N

    2015-02-01

    The cytosolic sulfotransferases (SULTs) are dimeric enzymes that help maintain homeostasis through the modulation of hormone and drug activity by catalyzing their transformation into hydrophilic sulfate esters and increasing their excretion. Each of the thirteen active human SULT isoforms displays a unique substrate specificity pattern that underlies its individual role in our bodies. These specificities have proven to be complex, in some cases masking the biological role of specific isoforms. The first part of this review offers a short summary of historical underpinnings of human SULTs, primarily centered on the characterization of each isoform's kinetic and structural properties. Recent structural investigations have revealed each SULT has an active site "lid" that undergoes restructuring once the cofactor/sulfonate donor, 3'-phosphoadenosine-5'-phosphosulfate (PAPS), binds to the enzyme. This structural rearrangement can alter substrate-binding profiles, therefore complicating enzyme/substrate interactions and making substrate/cosubstrate concentrations and binding order important considerations in enzyme functionality. Molecular dynamic simulations have recently been employed to describe this restructuring in an attempt to offer insight to its effects on substrate selectivity. In addition to reviewing new data on SULT molecular dynamics, we will discuss the contribution of PAPS concentrations and SULT dimerization in the regulation of SULT activity within the human body.

  13. MUTZ-3 derived Langerhans cells in human skin equivalents show differential migration and phenotypic plasticity after allergen or irritant exposure

    Energy Technology Data Exchange (ETDEWEB)

    Kosten, Ilona J.; Spiekstra, Sander W. [Department of Dermatology, VU University Medical Center, Amsterdam (Netherlands); Gruijl, Tanja D. de [Department of Dermatology Medical Oncology, VU University Medical Center, Amsterdam (Netherlands); Gibbs, Susan, E-mail: s.gibbs@acta.nl [Department of Dermatology, VU University Medical Center, Amsterdam (Netherlands); Department of Oral Cell Biology, Academic Center for Dentistry (ACTA), Amsterdam (Netherlands)

    2015-08-15

    After allergen or irritant exposure, Langerhans cells (LC) undergo phenotypic changes and exit the epidermis. In this study we describe the unique ability of MUTZ-3 derived Langerhans cells (MUTZ-LC) to display similar phenotypic plasticity as their primary counterparts when incorporated into a physiologically relevant full-thickness skin equivalent model (SE-LC). We describe differences and similarities in the mechanisms regulating LC migration and plasticity upon allergen or irritant exposure. The skin equivalent consisted of a reconstructed epidermis containing primary differentiated keratinocytes and CD1a{sup +} MUTZ-LC on a primary fibroblast-populated dermis. Skin equivalents were exposed to a panel of allergens and irritants. Topical exposure to sub-toxic concentrations of allergens (nickel sulfate, resorcinol, cinnamaldehyde) and irritants (Triton X-100, SDS, Tween 80) resulted in LC migration out of the epidermis and into the dermis. Neutralizing antibody to CXCL12 blocked allergen-induced migration, whereas anti-CCL5 blocked irritant-induced migration. In contrast to allergen exposure, irritant exposure resulted in cells within the dermis becoming CD1a{sup −}/CD14{sup +}/CD68{sup +} which is characteristic of a phenotypic switch of MUTZ-LC to a macrophage-like cell in the dermis. This phenotypic switch was blocked with anti-IL-10. Mechanisms previously identified as being involved in LC activation and migration in native human skin could thus be reproduced in the in vitro constructed skin equivalent model containing functional LC. This model therefore provides a unique and relevant research tool to study human LC biology in situ under controlled in vitro conditions, and will provide a powerful tool for hazard identification, testing novel therapeutics and identifying new drug targets. - Highlights: • MUTZ-3 derived Langerhans cells integrated into skin equivalents are fully functional. • Anti-CXCL12 blocks allergen-induced MUTZ-LC migration.

  14. Th17 plasticity in human autoimmune arthritis is driven by the inflammatory environment

    OpenAIRE

    Nistala, Kiran; Adams, Stuart; Cambrook, Helen; Ursu, Simona; Olivito, Biagio; de Jager, Wilco; Evans, Jamie G.; Cimaz, Rolando; Bajaj-Elliott, Mona; Wedderburn, Lucy R.

    2010-01-01

    In several murine models of autoimmune arthritis, Th17 cells are the dominant initiators of inflammation. In human arthritis the majority of IL-17–secreting cells within the joint express a cytokine phenotype intermediate between Th17 and Th1. Here we show that Th17/1 cells from the joints of children with inflammatory arthritis express high levels of both Th17 and Th1 lineage-specific transcription factors, RORC2 and T-bet. Modeling the generation of Th17/1 in vitro, we show that Th17 cells ...

  15. Intranasal administration of oxytocin increases human aggressive behavior.

    Science.gov (United States)

    Ne'eman, R; Perach-Barzilay, N; Fischer-Shofty, M; Atias, A; Shamay-Tsoory, S G

    2016-04-01

    Considering its role in prosocial behaviors, oxytocin (OT) has been suggested to diminish levels of aggression. Nevertheless, recent findings indicate that oxytocin may have a broader influence on increasing the salience of social stimuli and may therefore, under certain circumstances, increase antisocial behaviors such as aggression. This controversy led to the following speculations: If indeed oxytocin promotes primarily prosocial behavior, administration of OT is expected to diminish levels of aggression. However, if oxytocin mainly acts to increase the salience of social stimuli, it is expected to elevate levels of aggression following provocation. In order to test this assumption we used the Social Orientation Paradigm (SOP), a monetary game played against a fictitious partner that allows measuring three types of responses in the context of provocation: an aggressive response - reducing a point from the fictitious partner, an individualistic response - adding a point to oneself, and a collaborative response - adding half a point to the partner and half a point to oneself. In the current double-blind, placebo-controlled, within-subject study design, 45 participants completed the SOP task following the administration of oxytocin or placebo. The results indicated that among subjects naïve to the procedure oxytocin increased aggressive responses in comparison with placebo. These results support the saliency hypothesis of oxytocin and suggest that oxytocin plays a complex role in the modulation of human behavior.

  16. Gas Experiments with Plastic Soda Bottles.

    Science.gov (United States)

    Kavanah, Patrick; Zipp, Arden P.

    1998-01-01

    Describes the use of an inexpensive device consisting of a plastic soda bottle and a modified plastic cap in a range of demonstrations and experimental activities having to do with the behavior of gases. (Author/WRM)

  17. Neonatal thymectomy reveals differentiation and plasticity within human naive T cells

    Science.gov (United States)

    van den Broek, Theo; Delemarre, Eveline M.; Janssen, Willemijn J.M.; Nievelstein, Rutger A.J.; Broen, Jasper C.; Tesselaar, Kiki; Borghans, Jose A.M.; Nieuwenhuis, Edward E.S.; Prakken, Berent J.; Mokry, Michal; Jansen, Nicolaas J.G.

    2016-01-01

    The generation of naive T cells is dependent on thymic output, but in adults, the naive T cell pool is primarily maintained by peripheral proliferation. Naive T cells have long been regarded as relatively quiescent cells; however, it was recently shown that IL-8 production is a signatory effector function of naive T cells, at least in newborns. How this functional signature relates to naive T cell dynamics and aging is unknown. Using a cohort of children and adolescents who underwent neonatal thymectomy, we demonstrate that the naive CD4+ T cell compartment in healthy humans is functionally heterogeneous and that this functional diversity is lost after neonatal thymectomy. Thymic tissue regeneration later in life resulted in functional restoration of the naive T cell compartment, implicating the thymus as having functional regenerative capacity. Together, these data shed further light on functional differentiation within the naive T cell compartment and the importance of the thymus in human naive T cell homeostasis and premature aging. In addition, these results affect and alter our current understanding on the identification of truly naive T cells and recent thymic emigrants. PMID:26901814

  18. Retrotransposon-Encoded Reverse Transcriptase in the Genesis, Progression and Cellular Plasticity of Human Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sinibaldi-Vallebona, Paola; Matteucci, Claudia [Department of Experimental Medicine and Biochemical Sciences, University ‘Tor Vergata’, Rome (Italy); Spadafora, Corrado, E-mail: cspadaf@tin.it [Italian National Institute of Health (ISS), Rome (Italy)

    2011-03-07

    LINE-1 (Long Interspersed Nuclear Elements) and HERVs (Human Endogenous Retroviruses) are two families of autonomously replicating retrotransposons that together account for about 28% of the human genome. Genes harbored within LINE-1 and HERV retrotransposons, particularly those encoding the reverse transcriptase (RT) enzyme, are generally expressed at low levels in differentiated cells, but their expression is upregulated in transformed cells and embryonic tissues. Here we discuss a recently discovered RT-dependent mechanism that operates in tumorigenesis and reversibly modulates phenotypic and functional variations associated with tumor progression. Downregulation of active LINE-1 elements drastically reduces the tumorigenic potential of cancer cells, paralleled by reduced proliferation and increased differentiation. Pharmacological RT inhibitors (e.g., nevirapine and efavirenz) exert similar effects on tumorigenic cell lines, both in culture and in animal models. The HERV-K family play a distinct complementary role in stress-dependent transition of melanoma cells from an adherent, non-aggressive, to a non-adherent, highly malignant, growth phenotype. In synthesis, the retrotransposon-encoded RT is increasingly emerging as a key regulator of tumor progression and a promising target in a novel anti-cancer therapy.

  19. Rheology of human blood plasma: Viscoelastic versus Newtonian behavior

    CERN Document Server

    Brust, M; Pan, L; Garcia, M; Arratia, P E; Wagner, C; 10.1103/PhysRevLett.110.078305

    2013-01-01

    We investigate the rheological characteristics of human blood plasma in shear and elongational flows. While we can confirm a Newtonian behavior in shear flow within experimental resolution, we find a viscoelastic behavior of blood plasma in the pure extensional flow of a capillary break-up rheometer. The influence of the viscoelasticity of blood plasma on capillary blood flow is tested in a microfluidic device with a contraction-expansion geometry. Differential pressure measurements revealed that the plasma has a pronounced flow resistance compared to that of pure water. Supplementary measurements indicate that the viscoelasticity of the plasma might even lead to viscoelastic instabilities under certain conditions. Our findings show that the viscoelastic properties of plasma should not be ignored in future studies on blood flow.

  20. Endocrinology of human female sexuality, mating, and reproductive behavior.

    Science.gov (United States)

    Motta-Mena, Natalie V; Puts, David A

    2016-11-17

    Hormones orchestrate and coordinate human female sexual development, sexuality, and reproduction in relation to three types of phenotypic changes: life history transitions such as puberty and childbirth, responses to contextual factors such as caloric intake and stress, and cyclical patterns such as the ovulatory cycle. Here, we review the endocrinology underlying women's reproductive phenotypes, including sexual orientation and gender identity, mate preferences, competition for mates, sex drive, and maternal behavior. We highlight distinctive aspects of women's sexuality such as the possession of sexual ornaments, relatively cryptic fertile windows, extended sexual behavior across the ovulatory cycle, and a period of midlife reproductive senescence-and we focus on how hormonal mechanisms were shaped by selection to produce adaptive outcomes. We conclude with suggestions for future research to elucidate how hormonal mechanisms subserve women's reproductive phenotypes.

  1. Is Sleep Essential for Neural Plasticity in Humans, and How Does It Affect Motor and Cognitive Recovery?

    National Research Council Canada - National Science Library

    Gorgoni, Maurizio; D'Atri, Aurora; Lauri, Giulia; Rossini, Paolo Maria; Ferlazzo, Fabio; De Gennaro, Luigi

    2013-01-01

    ... exists today that sleep is strictly linked to memory, learning and, in general, to the mechanisms of neural plasticity. Indeed, cognitive impairments, especially in learning, and memory tasks [57], are one of the main consequences of sleep deprivation. Although the link between sleep, memory, and neural plasticity has been widely investigated, such...

  2. Human behavior research and the design of sustainable transport systems

    Science.gov (United States)

    Schauer, James J.

    2011-09-01

    Transport currently represents approximately 19% of the global energy demand and accounts for about 23% of the global carbon dioxide emissions (IEA 2009). As the demand for mobility is expected to continue to increase in the coming decades, the stabilization of atmospheric carbon dioxide levels will require the evolution of transport, along with power generation, building design and manufacturing. The continued development of these sectors will need to include changes in energy sources, energy delivery, materials, infrastructure and human behavior. Pathways to reducing carbon from the transport sector have unique challenges and opportunities that are inherent to the human choices and behavioral patterns that mold the transportation systems and the associated energy needs. Technology, government investment, and regulatory policies have a significant impact on the formulation of transportation infrastructure; however, the role of human behavior and public acceptance on the efficiency and effectiveness of transport systems should not be underestimated. Although developed, rapidly developing, and underdeveloped nations face different challenges in the establishment of transport infrastructure that can meet transport needs while achieving sustainable carbon dioxide emissions, the constraints that establish the domain of possibilities are closely related for all nations. These constraints include capital investment, fuel supplies, power systems, and human behavior. Throughout the world, there are considerable efforts directed at advancing and optimizing the financing of sustainable infrastructures, the production of low carbon fuels, and the production of advanced power systems, but the foundational work on methods to understand human preferences and behavior within the context of transport and the valuation of reductions in carbon dioxide emissions is greatly lagging behind. These methods and the associated understanding of human behavior and the willingness to pay for

  3. Understanding the behavior of floodplains as human-water systems

    Science.gov (United States)

    Di Baldassarre, G.; Brandimarte, L.

    2012-12-01

    Floodplains are among the most valuable ecosystems for supporting biodiversity and providing services to the environment. Moreover, they are home of approximately one-sixth of the world population as they offer favorable conditions for economic development. As a result, flood disasters currently affect more than 100 million people a year. Sadly, flood losses and fatalities are expected to increase further in many countries because of population growth as well as changes in land use and climate. Given the relevance of floodplain systems, a number of social scientists have examined how the frequency and severity of flooding often determine whether human development in floodplains is desirable or not. Meanwhile, many earth scientists have investigated the impact of human activities (e.g. land-use changes, urbanization, river training) on the frequency and magnitude of floods. In fact, as human activities change the frequency of flooding, the frequency of flooding affects human developments in floodplain areas. Yet, these dynamic interactions between floods and societies and the associated feedback mechanisms remain largely unexplored and poorly understood. As a result, we typically consider humans as external forcing (or boundary condition) without representing the feedback loops and our prediction of future trajectories are therefore extremely limited. This presentation shows a first attempt to understand the behavior of floodplains as coupled human-water systems. In particular, we analyzed a number of long time series of hydrological and population data in the Po River Basin (Italy) to explore the feedback mechanisms, reciprocal effects, surprises, and threshold mechanisms, taking place in floodplain systems. The outcomes of the study enable a better understanding of how the occurrences of floods shape human developments while, at the same time, human activities shape the magnitude and frequency of floods. The presentation also discusses the opportunities offered by

  4. Plasticity of human spatial cognition: spatial language and cognition covary across cultures.

    Science.gov (United States)

    Haun, Daniel B M; Rapold, Christian J; Janzen, Gabriele; Levinson, Stephen C

    2011-04-01

    The present paper explores cross-cultural variation in spatial cognition by comparing spatial reconstruction tasks by Dutch and Namibian elementary school children. These two communities differ in the way they predominantly express spatial relations in language. Four experiments investigate cognitive strategy preferences across different levels of task-complexity and instruction. Data show a correlation between dominant linguistic spatial frames of reference and performance patterns in non-linguistic spatial memory tasks. This correlation is shown to be stable across an increase of complexity in the spatial array. When instructed to use their respective non-habitual cognitive strategy, participants were not easily able to switch between strategies and their attempts to do so impaired their performance. These results indicate a difference not only in preference but also in competence and suggest that spatial language and non-linguistic preferences and competences in spatial cognition are systematically aligned across human populations.

  5. Human ketosteroid receptors interact with hazardous phthalate plasticizers and their metabolites: an in silico study.

    Science.gov (United States)

    Sarath Josh, M K; Pradeep, S; Vijayalekshmy Amma, K S; Sudha Devi, R; Balachandran, S; Sreejith, M N; Benjamin, Sailas

    2016-06-01

    Phthalic acid esters or phthalates are ubiquitous environmental pollutants known for their adverse health effects in test animals and, of late, in humans. Thus, in this molecular docking study - using Glide (Schrödinger) - the molecular interactions of 31 ligands, including 12 diphthalates, their monophthalates and phthalic acid with selected human ketosteroid receptors, i.e., androgen (hAR), progesterone (hPR) and glucocorticoid (hGR) receptors were explored and their binding affinities were compared with that of corresponding natural steroids and a known endocrine disrupting xenobiotic, bisphenol A (BPA). Mostly, diphthalates and monophthalates showed the potential for antisteroidal activity by interacting with hAR, hPR and hGR. Of them, diphenyl phthalate showed the highest G score (-7.70 kcal mol(-1) ) with hAR, and the crucial amino acid (aa) residues in the ligand binding domain (LBD) of this receptor involved in the molecular interactions were Phe 764, Leu 704, Asn 705 and Thr 877. The mono-iso-decyl phthalate showed the highest G score (-8.36) with the hPR, and the crucial aa residues in the LBD interactions were Arg 766 Gln 725 and Phe 778. The mono-iso-decyl phthalate also showed more affinity (-8.44) towards hGR than the natural ligand, and the aa residues in the LBD interactions were Gln 570 and Met 604. In addition to these, some other phthalates established comparable interactions with certain aa residues located in the LBD of these receptors, which resulted in higher G scores. Contrastingly, BPA and some natural ligands tested in this study showed lower G scores with these receptors than certain phthalates reported herein, i.e., certain phthalates are more toxic than the proven toxic BPA. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Deformation mechanisms of plasticized starch materials.

    Science.gov (United States)

    Mikus, P-Y; Alix, S; Soulestin, J; Lacrampe, M F; Krawczak, P; Coqueret, X; Dole, P

    2014-12-19

    The aim of this paper is to understand the influence of plasticizer and plasticizer amount on the mechanical and deformation behaviors of plasticized starch. Glycerol, sorbitol and mannitol have been used as plasticizers. After extrusion of the various samples, dynamic mechanical analyses and video-controlled tensile tests have been performed. It was found that the nature of plasticizer, its amount as well as the aging of the material has an impact on the involved deformation mechanism. The variations of volume deformation could be explained by an antiplasticization effect (low plasticizer amount), a phase-separation phenomenon (excess of plasticizer) and/or by the retrogradation of starch.

  7. Microstructure and annealing behavior of a modified 9Cr-1Mo steel after dynamic plastic deformation to different strains

    DEFF Research Database (Denmark)

    Zhang, Zhenbo; Mishin, Oleg; Tao, N.R.;

    2015-01-01

    The microstructure, hardness and tensile properties of a modified 9Cr-1Mo steel processed by dynamic plastic deformation (DPD) to different strains (0.5 and 2.3) have been investigated in the as-deformed and annealed conditions. It is found that significant structural refinement and a high level...... of strength can be achieved by DPD to a strain of 2.3, and that the microstructure at this strain contains a large fraction of high angle boundaries. The ductility of the DPD processed steel is however low. Considerable structural coarsening of the deformed microstructure without pronounced recrystallization...

  8. Human Wharton's Jelly Mesenchymal Stem Cells plasticity augments scar-free skin wound healing with hair growth.

    Science.gov (United States)

    Sabapathy, Vikram; Sundaram, Balasubramanian; V M, Sreelakshmi; Mankuzhy, Pratheesh; Kumar, Sanjay

    2014-01-01

    Human mesenchymal stem cells (MSCs) are a promising candidate for cell-based transplantation and regenerative medicine therapies. Thus in the present study Wharton's Jelly Mesenchymal Stem Cells (WJ-MSCs) have been derived from extra embryonic umbilical cord matrix following removal of both arteries and vein. Also, to overcome the clinical limitations posed by fetal bovine serum (FBS) supplementation because of xenogeneic origin of FBS, usual FBS cell culture supplement has been replaced with human platelet lysate (HPL). Apart from general characteristic features of bone marrow-derived MSCs, wharton jelly-derived MSCs have the ability to maintain phenotypic attributes, cell growth kinetics, cell cycle pattern, in vitro multilineage differentiation plasticity, apoptotic pattern, normal karyotype-like intrinsic mesenchymal stem cell properties in long-term in vitro cultures. Moreover, the WJ-MSCs exhibited the in vitro multilineage differentiation capacity by giving rise to differentiated cells of not only mesodermal lineage but also to the cells of ectodermal and endodermal lineage. Also, WJ-MSC did not present any aberrant cell state upon in vivo transplantation in SCID mice and in vitro soft agar assays. The immunomodulatory potential assessed by gene expression levels of immunomodulatory factors upon exposure to inflammatory cytokines in the fetal WJ-MSCs was relatively higher compared to adult bone marrow-derived MSCs. WJ-MSCs seeded on decellularized amniotic membrane scaffold transplantation on the skin injury of SCID mice model demonstrates that combination of WJ-MSCs and decellularized amniotic membrane scaffold exhibited significantly better wound-healing capabilities, having reduced scar formation with hair growth and improved biomechanical properties of regenerated skin compared to WJ-MSCs alone. Further, our experimental data indicate that indocyanin green (ICG) at optimal concentration can be resourcefully used for labeling of stem cells and in vivo

  9. Human Wharton's Jelly Mesenchymal Stem Cells plasticity augments scar-free skin wound healing with hair growth.

    Directory of Open Access Journals (Sweden)

    Vikram Sabapathy

    Full Text Available Human mesenchymal stem cells (MSCs are a promising candidate for cell-based transplantation and regenerative medicine therapies. Thus in the present study Wharton's Jelly Mesenchymal Stem Cells (WJ-MSCs have been derived from extra embryonic umbilical cord matrix following removal of both arteries and vein. Also, to overcome the clinical limitations posed by fetal bovine serum (FBS supplementation because of xenogeneic origin of FBS, usual FBS cell culture supplement has been replaced with human platelet lysate (HPL. Apart from general characteristic features of bone marrow-derived MSCs, wharton jelly-derived MSCs have the ability to maintain phenotypic attributes, cell growth kinetics, cell cycle pattern, in vitro multilineage differentiation plasticity, apoptotic pattern, normal karyotype-like intrinsic mesenchymal stem cell properties in long-term in vitro cultures. Moreover, the WJ-MSCs exhibited the in vitro multilineage differentiation capacity by giving rise to differentiated cells of not only mesodermal lineage but also to the cells of ectodermal and endodermal lineage. Also, WJ-MSC did not present any aberrant cell state upon in vivo transplantation in SCID mice and in vitro soft agar assays. The immunomodulatory potential assessed by gene expression levels of immunomodulatory factors upon exposure to inflammatory cytokines in the fetal WJ-MSCs was relatively higher compared to adult bone marrow-derived MSCs. WJ-MSCs seeded on decellularized amniotic membrane scaffold transplantation on the skin injury of SCID mice model demonstrates that combination of WJ-MSCs and decellularized amniotic membrane scaffold exhibited significantly better wound-healing capabilities, having reduced scar formation with hair growth and improved biomechanical properties of regenerated skin compared to WJ-MSCs alone. Further, our experimental data indicate that indocyanin green (ICG at optimal concentration can be resourcefully used for labeling of stem cells

  10. Neuronal plasticity of human Wharton's jelly mesenchymal stromal cells to the dopaminergic cell type compared with human bone marrow mesenchymal stromal cells.

    Science.gov (United States)

    Datta, Indrani; Mishra, Swati; Mohanty, Lipsa; Pulikkot, Sunitha; Joshi, Preeti G

    2011-09-01

    inducible release of dopamine was found to be similar between induced BM and WJ MSC, as measured by dopamine enzyme-linked immunosorbent assay (ELISA). Interestingly, an adenosine triphosphate (ATP)-stimulated change in intracellular Ca(2+) was observed in both control and induced MSC, but only the induced MSC was capable of releasing dopamine. Our data demonstrate that MSC from the two different sources respond similarly to inductive cues to differentiate terminally to a DA cell type, and the neuronal plasticity of human WJ MSC is comparable with that of BM MSC.

  11. From Hydra Regeneration to Human Brain Structural Plasticity: A Long Trip through Narrowing Roads

    Directory of Open Access Journals (Sweden)

    Luca Bonfanti

    2011-01-01

    Full Text Available Regeneration is a strategy to maintain form and function throughout life. Studies carried out on animal models throughout the phylogenetic tree have flourished in the last decades in search of mechanisms underlying the regenerative processes. The development of such studies is strictly linked with stem cell research and both are viewed as one of the most promising outcomes for regenerative medicine; yet, regeneration, stem cells, and tissue repair do not seem to follow a logical path through the different animal species and tissues. As a result, some mammalian organs, e.g., kidney and brain, have lost most of their regenerative capacity. The human nervous system, although harboring neural stem cells, is placed at the extreme of “perennial” tissues. In addition, it is affected by neurodegenerative diseases, whose heavy burden is heightened by enhanced life spans. This review, starting from the basic principles of tissue regeneration viewed in a comparative context, tries to answer this question: To which extent can regenerative medicine be figured out in a mammalian brain equipped with many anatomical/evolutionary constraints?

  12. Flexible Human Behavior Analysis Framework for Video Surveillance Applications

    Directory of Open Access Journals (Sweden)

    Weilun Lao

    2010-01-01

    Full Text Available We study a flexible framework for semantic analysis of human motion from surveillance video. Successful trajectory estimation and human-body modeling facilitate the semantic analysis of human activities in video sequences. Although human motion is widely investigated, we have extended such research in three aspects. By adding a second camera, not only more reliable behavior analysis is possible, but it also enables to map the ongoing scene events onto a 3D setting to facilitate further semantic analysis. The second contribution is the introduction of a 3D reconstruction scheme for scene understanding. Thirdly, we perform a fast scheme to detect different body parts and generate a fitting skeleton model, without using the explicit assumption of upright body posture. The extension of multiple-view fusion improves the event-based semantic analysis by 15%–30%. Our proposed framework proves its effectiveness as it achieves a near real-time performance (13–15 frames/second and 6–8 frames/second for monocular and two-view video sequences.

  13. Is Sleep Essential for Neural Plasticity in Humans, and How Does It Affect Motor and Cognitive Recovery?

    Directory of Open Access Journals (Sweden)

    Maurizio Gorgoni

    2013-01-01

    Full Text Available There is a general consensus that sleep is strictly linked to memory, learning, and, in general, to the mechanisms of neural plasticity, and that this link may directly affect recovery processes. In fact, a coherent pattern of empirical findings points to beneficial effect of sleep on learning and plastic processes, and changes in synaptic plasticity during wakefulness induce coherent modifications in EEG slow wave cortical topography during subsequent sleep. However, the specific nature of the relation between sleep and synaptic plasticity is not clear yet. We reported findings in line with two models conflicting with respect to the underlying mechanisms, that is, the “synaptic homeostasis hypothesis” and the “consolidation” hypothesis, and some recent results that may reconcile them. Independently from the specific mechanisms involved, sleep loss is associated with detrimental effects on plastic processes at a molecular and electrophysiological level. Finally, we reviewed growing evidence supporting the notion that plasticity-dependent recovery could be improved managing sleep quality, while monitoring EEG during sleep may help to explain how specific rehabilitative paradigms work. We conclude that a better understanding of the sleep-plasticity link could be crucial from a rehabilitative point of view.

  14. Is sleep essential for neural plasticity in humans, and how does it affect motor and cognitive recovery?

    Science.gov (United States)

    Gorgoni, Maurizio; D'Atri, Aurora; Lauri, Giulia; Rossini, Paolo Maria; Ferlazzo, Fabio; De Gennaro, Luigi

    2013-01-01

    There is a general consensus that sleep is strictly linked to memory, learning, and, in general, to the mechanisms of neural plasticity, and that this link may directly affect recovery processes. In fact, a coherent pattern of empirical findings points to beneficial effect of sleep on learning and plastic processes, and changes in synaptic plasticity during wakefulness induce coherent modifications in EEG slow wave cortical topography during subsequent sleep. However, the specific nature of the relation between sleep and synaptic plasticity is not clear yet. We reported findings in line with two models conflicting with respect to the underlying mechanisms, that is, the "synaptic homeostasis hypothesis" and the "consolidation" hypothesis, and some recent results that may reconcile them. Independently from the specific mechanisms involved, sleep loss is associated with detrimental effects on plastic processes at a molecular and electrophysiological level. Finally, we reviewed growing evidence supporting the notion that plasticity-dependent recovery could be improved managing sleep quality, while monitoring EEG during sleep may help to explain how specific rehabilitative paradigms work. We conclude that a better understanding of the sleep-plasticity link could be crucial from a rehabilitative point of view.

  15. Effect of Nb on plasticity and oxidation behavior of TiA1Nb intermetallic compound by density functional theory

    Institute of Scientific and Technical Information of China (English)

    LI Yan-feng; XU Hui; SONG Zhao-quan; MA Song-shan

    2010-01-01

    Based on the pseudo potential plane-wave method of density functional theory(DFT),Ti1-xNbxA1(x=0,0.062 5,0.083 3,0.125,0.250)crystals' geometry structure,elastic constants,electronic structure and Mulliken populations were calculated,and the effects of doping on the geometric structure,electronic structure and bond strength were systematically analyzed.The results show that the influence of Nb on the geometric structure is little in terms of the plasticity,and with the increase of Nb content,the covalent bond strength remarkably reduces,and Ti-A1,Nb-M(M=Ti,A1)and other hybrid bonds enhance; meanwhile,the peak district increases and the pseudo-energy gap first decreases and then increases,the overall band structure narrows,the covalent bond and direction of bonds reduce.The population analysis also shows that the results are consistent with the electronic structure analysis.The density of states of TiAlNb shows that Nb doping can enhance the activity of Al and benefit the form of Al2O3 film.All the calculations reveal that the room temperature plasticity and the antioxidation properties of the compounds can be improved with the Nb content of 8.33%-12.5%(mole fraction).

  16. Pericyte plasticity - comparative investigation of the angiogenic and multilineage potential of pericytes from different human tissues.

    Science.gov (United States)

    Herrmann, M; Bara, J J; Sprecher, C M; Menzel, U; Jalowiec, J M; Osinga, R; Scherberich, A; Alini, M; Verrier, S

    2016-04-10

    Pericyte recruitment is essential for the stability of newly formed vessels. It was also suggested that pericytes represent common ancestor cells giving rise to mesenchymal stem cells (MSCs) in the adult. Here, we systematically investigated pericytes and MSCs from different human tissues in terms of their angiogenic and multilineage differentiation potential in vitro in order to assess the suitability of the different cell types for the regeneration of vascularised tissues. Magnetic-activated cell sorting (MACS®) was used to enrich CD34-CD146+ pericytes from adipose tissue (AT) and bone marrow (BM). The multilineage potential of pericytes was assessed by testing their capability to differentiate towards osteogenic, adipogenic and chondrogenic lineage in vitro. Pericytes and endothelial cells were co-seeded on Matrigel™ and the formation of tube-like structures was examined to study the angiogenic potential of pericytes. MSCs from AT and BM were used as controls. CD34-CD146+ cells were successfully enriched from AT and BM. Only BM-derived cells exhibited trilineage differentiation potential. AT-derived cells displayed poor chondrogenic differentiation upon stimulation with transforming growth factor-β1. Interestingly, osteogenic differentiation was more efficient in AT-PC and BM-PC compared to the respective full MSC population. Matrigel™ assays revealed that pericytes from all tissues integrated into tube-like structures. We show that MACS®-enriched pericytes from BM and AT have the potential to regenerate tissues of different mesenchymal lineages and support neovascularisation. MACS® represents a simple enrichment strategy of cells, which is of particular interest for clinical application. Finally, our results suggest that the regenerative potential of pericytes depends on their tissue origin, which is an important consideration for future studies.

  17. Is the human mirror neuron system plastic? Evidence from a transcranial magnetic stimulation study.

    Science.gov (United States)

    Mehta, Urvakhsh Meherwan; Waghmare, Avinash V; Thirthalli, Jagadisha; Venkatasubramanian, Ganesan; Gangadhar, Bangalore N

    2015-10-01

    Virtual lesions in the mirror neuron network using inhibitory low-frequency (1Hz) transcranial magnetic stimulation (TMS) have been employed to understand its spatio-functional properties. However, no studies have examined the influence of neuro-enhancement by using excitatory high-frequency (20Hz) repetitive transcranial magnetic stimulation (HF-rTMS) on these networks. We used three forms of TMS stimulation (HF-rTMS, single and paired pulse) to investigate whether the mirror neuron system facilitates the motor system during goal-directed action observation relative to inanimate motion (motor resonance), a marker of putative mirror neuron activity. 31 healthy individuals were randomized to receive single-sessions of true or sham HF-rTMS delivered to the left inferior frontal gyrus - a component of the human mirror system. Motor resonance was assessed before and after HF-rTMS using three TMS cortical reactivity paradigms: (a) 120% of resting motor threshold (RMT), (b) stimulus intensity set to evoke motor evoked potential of 1-millivolt amplitude (SI1mV) and (c) a short latency paired pulse paradigm. Two-way RMANOVA showed a significant group (true versus sham) X occasion (pre- and post-HF-rTMS motor resonance) interaction effect for SI1mV [F(df)=6.26 (1, 29), p=0.018] and 120% RMT stimuli [F(df)=7.01 (1, 29), p=0.013] indicating greater enhancement of motor resonance in the true HF-rTMS group than the sham-group. This suggests that HF-rTMS could adaptively modulate properties of the mirror neuron system. This neuro-enhancement effect is a preliminary step that can open translational avenues for novel brain stimulation therapeutics targeting social-cognition deficits in schizophrenia and autism. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Task-concurrent anodal tDCS modulates bilateral plasticity in the human suprahyoid motor cortex

    Directory of Open Access Journals (Sweden)

    Shaofeng eZhao

    2015-06-01

    Full Text Available Transcranial direct current stimulation (tDCS is a non-invasive method to modulate cortical excitability in humans. Here, we examined the effects of anodal tDCS on suprahyoid motor evoked potentials (MEP when applied over the hemisphere with stronger and weaker suprahyoid/submental projections, respectively, while study participants performed a swallowing task. 30 healthy volunteers were invited to two experimental sessions and randomly assigned to one of two different groups. While in the first group stimulation was targeted over the hemisphere with stronger suprahyoid projections, the second group received stimulation over the weaker suprahyoid projections. tDCS was applied either as anodal or sham stimulation in a random cross-over design. Suprahyoid MEPs were assessed immediately before intervention, as well as 5, 30, 60, and 90 min after discontinuation of stimulation from both the stimulated and non-stimulated contralateral hemisphere. We found that anodal tDCS (a-tDCS had long-lasting effects on suprahyoid MEPs on the stimulated side in both groups (tDCS targeting the stronger projections: F(1,14 = 96.2, p < 0.001; tDCS targeting the weaker projections: F(1,14 = 37.45, p < 0.001. While MEPs did not increase when elicited from the non-targeted hemisphere after stimulation of the stronger projections (F(1,14 = 0.69, p = 0.42, we found increased MEPs elicited from the non-targeted hemisphere after stimulating the weaker projections (at time points 30 to 90 min (F(1,14 = 18.26, p = 0.001. We conclude that anodal tDCS has differential effects on suprahyoid MEPs elicited from the targeted and non-targeted hemisphere depending on the site of stimulation. This finding may be important for the application of a-tDCS in patients with dysphagia, for example after stroke.

  19. The Scent of Blood: A Driver of Human Behavior?

    Science.gov (United States)

    Moran, James K; Dietrich, Daniel R; Elbert, Thomas; Pause, Bettina M; Kübler, Lisa; Weierstall, Roland

    2015-01-01

    The scent of blood is potentially one of the most fundamental and survival-relevant olfactory cues in humans. This experiment tests the first human parameters of perceptual threshold and emotional ratings in men and women of an artificially simulated smell of fresh blood in contact with the skin. We hypothesize that this scent of blood, with its association with injury, danger, death, and nutrition will be a critical cue activating fundamental motivational systems relating to either predatory approach behavior or prey-like withdrawal behavior, or both. The results show that perceptual thresholds are unimodally distributed for both sexes, with women being more sensitive. Furthermore, both women and men's emotional responses to simulated blood scent divide strongly into positive and negative valence ratings, with negative ratings in women having a strong arousal component. For women, this split is related to the phase of their menstrual cycle and oral contraception (OC). Future research will investigate whether this split in both genders is context-dependent or trait-like.

  20. Understanding and Predicting Human Behavior for Social Communities

    Science.gov (United States)

    Simoes, Jose; Magedanz, Thomas

    Over the last years, with the rapid advance in technology, it is becoming increasingly feasible for people to take advantage of the devices and services in the surrounding environment to remain "connected" and continuously enjoy the activity they are engaged in, be it sports, entertainment, or work. Such a ubiquitous computing environment will allow everyone permanent access to the Internet anytime, anywhere and anyhow [1]. Nevertheless, despite the evolution of services, social aspects remain in the roots of every human behavior and activities. Great examples of such phenomena are online social networks, which engage users in a way never seen before in the online world. At the same time, being aware and communicating context is a key part of human interaction and is a particularly powerful concept when applied to a community of users where services can be made more personalized and useful. Altogether, harvesting context to reason and learn about user behavior will further enhance the future multimedia vision where services can be composed and customized according to user context. Moreover, it will help us to understand users in a better way.

  1. Thermomechanical behavior of human carotid arteries in the passive state.

    Science.gov (United States)

    Guinea, G V; Atienza, J M; Elices, M; Aragoncillo, P; Hayashi, K

    2005-06-01

    Localized heating or cooling is expanding the clinical procedures used to treat cardiovascular diseases. Advantageous implementation and development of these methods are linked indissolubly to a deeper understanding of the arterial response to combined mechanical and thermal loads. Despite this, the basic thermomechanical behavior of human blood vessels still remains largely unknown, primarily due to the lack of appropriate experimental data. In this work, the influence of temperature on the passive behavior of human carotid arteries was studied in vitro by means of inflation tests. Eleven carotid segments were tested in the range 0-200 mmHg at four different temperatures of 17, 27, 37, and 42 degrees C. The results show that the combined change of temperature and stress has a dramatic effect on the dilatation coefficient of the arterial wall, which is shifted from negative to positive depending on the stress state, whereas the structural stiffness of the arterial wall does not change appreciably in the range of temperatures tested.

  2. Social Media Research, Human Behavior, and Sustainable Society

    Directory of Open Access Journals (Sweden)

    Quan Li

    2017-03-01

    Full Text Available A bibliometric analysis was conducted to review social media research from different perspectives during the period of 2008–2014 based on the Science Citation Index and Social Science Citation Index database. Using a collection of 10,042 articles related to social media, the bibliometric analysis revealed some interesting patterns and trend of the scientific outputs, major journals, subject categories, spatial distribution, international collaboration, and temporal evolution in keywords usage in social media studies. The research on social media has been characterized by rapid growth and dynamic collaboration, with a rising number of publications and citation. Communication, Sociology, Public, Environment & Occupational Health, Business, and Multidisciplinary Psychology were the five most common categories. Computers in Human Behavior was the journal with the most social media publications, and Computers & Education ranked first according to the average citations. The two most productive countries were the U.S. and UK, delivering about half of the publications. The proportion of China’s internationally collaborative publications was the highest. The University of Wisconsin, the University of Michigan, and Harvard University were three most productive institutions. Several keywords, such as “Facebook”, “Twitter”, “communication”, “Social Networking Sites”, “China”, “climate change”, “big data” and “social support” increasingly gained the popularity during the study period, indicating the research trends on human behavior and sustainability.

  3. EXTRACTING HUMAN BEHAVIORAL PATTERNS BY MINING GEO-SOCIAL NETWORKS

    Directory of Open Access Journals (Sweden)

    M. Forghani

    2014-10-01

    Full Text Available Accessibility of positioning technologies such as GPS offer the opportunity to store one’s travel experience and publish it on the web. Using this feature in web-based social networks and considering location information shared by users as a bridge connecting the users’ network to location information layer leads to the formation of Geo-Social Networks. The availability of large amounts of geographical and social data on these networks provides rich sources of information that can be utilized for studying human behavior through data analysis in a spatial-temporal-social context. This paper attempts to investigate the behavior of around 1150 users of Foursquare network by making use of their check-ins. The authors analyzed the metadata associated with the whereabouts of the users, with an emphasis on the type of places, to uncover patterns across different temporal and geographical scales for venue category usage. The authors found five groups of meaningful patterns that can explore region characteristics and recognize a number of major crowd behaviors that recur over time and space.

  4. The effect of laser-treated titanium surface on human gingival fibroblast behavior.

    Science.gov (United States)

    Baltriukienė, D; Sabaliauskas, V; Balčiūnas, E; Melninkaitis, A; Liutkevičius, E; Bukelskienė, V; Rutkūnas, V

    2014-03-01

    Surface modification, as a means of enhancing soft tissue integration in titanium would have significant advantages including less marginal bone resorption, predictable esthetic outcome, improved soft tissue stability, and seal against bacterial leakage. The aim of this study was to evaluate the effects of laser-roughened titanium surfaces on human gingival fibroblast (HGF) viability, proliferation, and adhesion. Titanium discs were ablated with impulse laser in four different patterns. Polished and sand-blasted titanium discs were used as control groups. Specimen surface properties were determined using optical profilometry and scanning electron microscopy. HGF behavior on modified surfaces was analyzed using cell adhesion, viability, proliferation, and ELISA assays. Results suggested that modified Ti surfaces did not affect the viability of HGFs and improved adhesion was measured in laser treatment groups after 24 h. However, proliferation study showed that the adsorbance of fibroblast cells after 72 h cultured on polished titanium was higher and comparable with that of control cells. As for focal adhesion kinase (FAK), cells grown on laser modified surfaces had higher expression of FAK as compared with polished titanium. In conclusion, tested laser-treated surfaces seem to favor HGF adhesion. There were no significant differences between different laser treatment groups. Copyright © 2013 Society of Plastics Engineers.

  5. A common polymorphism in the brain-derived neurotrophic factor gene (BDNF) modulates human cortical plasticity and the response to rTMS.

    Science.gov (United States)

    Cheeran, Binith; Talelli, Penelope; Mori, Francesco; Koch, Giacomo; Suppa, Antonio; Edwards, Mark; Houlden, Henry; Bhatia, Kailash; Greenwood, Richard; Rothwell, John C

    2008-12-01

    The brain-derived neurotrophic factor gene (BDNF) is one of many genes thought to influence synaptic plasticity in the adult brain and shows a common single nucleotide polymorphism (BDNF Val66Met) in the normal population that is associated with differences in hippocampal volume and episodic memory. It is also thought to influence possible synaptic changes in motor cortex following a simple motor learning task. Here we extend these studies by using new non-invasive transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (TDCS) techniques that directly test the excitability and plasticity of neuronal circuits in human motor cortex in subjects at rest. We investigated whether the susceptibility to TMS probes of plasticity is significantly influenced by the BDNF polymorphism. Val66Met carriers were matched with Val66Val individuals and tested on the following protocols: continuous and intermittent theta burst TMS; median nerve paired associative stimulation; and homeostatic plasticity in the TDCS/1 Hz rTMS model. The response of Met allele carriers differed significantly in all protocols compared with the response of Val66Val individuals. We suggest that this is due to the effect of BNDF on the susceptibility of synapses to undergo LTP/LTD. The circuits tested here are implicated in the pathophysiology of movement disorders such as dystonia and are being assessed as potential new targets in the treatment of stroke. Thus the polymorphism may be one factor that influences the natural response of the brain to injury and disease.

  6. Plastics Technology.

    Science.gov (United States)

    Barker, Tommy G.

    This curriculum guide is designed to assist junior high schools industrial arts teachers in planning new courses and revising existing courses in plastics technology. Addressed in the individual units of the guide are the following topics: introduction to production technology; history and development of plastics; safety; youth leadership,…

  7. The effect of inclination angle on the plastic deformation behavior of bicrystalline silver nanowires with Σ3 asymmetric tilt grain boundaries

    Science.gov (United States)

    Yuan, Lin; Jing, Peng; Shan, Debin; Guo, Bin

    2017-01-01

    Atomistic simulations were used to investigate the plastic deformation behavior of bicrystalline silver nanowires with Σ3 asymmetric tilt grain boundaries at 0.1 K. The calculated grain boundary energies of Σ3 asymmetric tilt grain boundaries corresponded well with the energies measured in experiments and predicted by the theoretical description. The Σ3 asymmetric tilt grain boundaries with low inclination angles were composed of a replication of twin boundary segments separated by small ledges. The results demonstrated that the combination effect of Schmid factor and non-Schmid factors could explain dislocations emission into grain 1 only in models with low inclination angles (Ф nanocrystalline materials and provide insights into the synthesis of nanocrystalline materials with superior strength and ductility.

  8. Effect of Specimen Size on the Tensile Strength Behavior of the Plastic Waste Fiber Reinforced Soil – Lime – Rice Husk Ash Mixtures

    Directory of Open Access Journals (Sweden)

    Muntohar A.S.

    2011-01-01

    Full Text Available Improvement of tensile strength in fiber reinforced soil is an important research topic. A study has been undertaken to investigate the strength of stabilized clay-soil reinforced with randomly distributed discrete plastic waste fibers by carrying out split tensile strength test. In this study, the clay soil was stabilized with lime and rice husk ash mixtures. The main purpose of this research is to investigate the effect of specimen size to the tensile strength behavior. Testing procedure was formulated using extended ASTM C496 standard. The laboratory investigation results showed that split-tensile strength of reinforced specimens increased with increase in size. The limitations of the dataset indicate that specimen size of 70 mm in diameter is the threshold to produce reasonable representative strengths.

  9. Human Behavioral Pharmacology, Past, Present, and Future: Symposium Presented at the 50th Annual Meeting of the Behavioral Pharmacology Society

    Science.gov (United States)

    Comer, Sandra D.; Bickel, Warren K.; Yi, Richard; de Wit, Harriet; Higgins, Stephen T.; Wenger, Galen R.; Johanson, Chris-Ellyn; Kreek, Mary Jeanne

    2010-01-01

    A symposium held at the 50th annual meeting of the Behavioral Pharmacology Society in May 2007 reviewed progress in the human behavioral pharmacology of drug abuse. Studies on drug self-administration in humans are reviewed that assessed reinforcing and subjective effects of drugs of abuse. The close parallels observed between studies in humans and laboratory animals using similar behavioral techniques have broadened our understanding of the complex nature of the pharmacological and behavioral factors controlling drug self-administration. The symposium also addressed the role that individual differences, such as gender, personality, and genotype play in determining the extent of self-administration of illicit drugs in human populations. Knowledge of how these factors influence human drug self-administration has helped validate similar differences observed in laboratory animals. In recognition that drug self-administration is but one of many choices available in the lives of humans, the symposium addressed the ways in which choice behavior can be studied in humans. These choice studies in human drug abusers have opened up new and exciting avenues of research in laboratory animals. Finally, the symposium reviewed behavioral pharmacology studies conducted in drug abuse treatment settings and the therapeutic benefits that have emerged from these studies. PMID:20664330

  10. Modification of hippocampal markers of synaptic plasticity by memantine in animal models of acute and repeated restraint stress: implications for memory and behavior.

    Science.gov (United States)

    Amin, Shaimaa Nasr; El-Aidi, Ahmed Amro; Ali, Mohamed Mostafa; Attia, Yasser Mahmoud; Rashed, Laila Ahmed

    2015-06-01

    Stress is any condition that impairs the balance of the organism physiologically or psychologically. The response to stress involves several neurohormonal consequences. Glutamate is the primary excitatory neurotransmitter in the central nervous system, and its release is increased by stress that predisposes to excitotoxicity in the brain. Memantine is an uncompetitive N-methyl D-aspartate glutamatergic receptors antagonist and has shown beneficial effect on cognitive function especially in Alzheimer's disease. The aim of the work was to investigate memantine effect on memory and behavior in animal models of acute and repeated restraint stress with the evaluation of serum markers of stress and the expression of hippocampal markers of synaptic plasticity. Forty-two male rats were divided into seven groups (six rats/group): control, acute restraint stress, acute restraint stress with Memantine, repeated restraint stress, repeated restraint stress with Memantine and Memantine groups (two subgroups as positive control). Spatial working memory and behavior were assessed by performance in Y-maze. We evaluated serum cortisol, tumor necrotic factor, interleukin-6 and hippocampal expression of brain-derived neurotrophic factor, synaptophysin and calcium-/calmodulin-dependent protein kinase II. Our results revealed that Memantine improved spatial working memory in repeated stress, decreased serum level of stress markers and modified the hippocampal synaptic plasticity markers in both patterns of stress exposure; in ARS, Memantine upregulated the expression of synaptophysin and brain-derived neurotrophic factor and downregulated the expression of calcium-/calmodulin-dependent protein kinase II, and in repeated restraint stress, it upregulated the expression of synaptophysin and downregulated calcium-/calmodulin-dependent protein kinase II expression.

  11. Human behavior in Prisoner's Dilemma experiments suppresses network reciprocity

    CERN Document Server

    Gracia-Lazaro, Carlos; Sanchez, Angel; Moreno, Yamir

    2012-01-01

    During the last few years, much research has been devoted to strategic interactions on complex networks. In this context, the Prisoner's Dilemma has become a paradigmatic model, and it has been established that imitative evolutionary dynamics lead to very different outcomes depending on the details of the network. We here report that when one takes into account the real behavior of people observed in the experiments, both at the mean-field level and on utterly different networks the observed level of cooperation is the same. We thus show that when human subjects interact in an heterogeneous mix including cooperators, defectors and moody conditional cooperators, the structure of the population does not promote or inhibit cooperation with respect to a well mixed population.

  12. Human behavior in Prisoner's Dilemma experiments suppresses network reciprocity.

    Science.gov (United States)

    Gracia-Lázaro, Carlos; Cuesta, José A; Sánchez, Angel; Moreno, Yamir

    2012-01-01

    During the last few years, much research has been devoted to strategic interactions on complex networks. In this context, the Prisoner's Dilemma has become a paradigmatic model, and it has been established that imitative evolutionary dynamics lead to very different outcomes depending on the details of the network. We here report that when one takes into account the real behavior of people observed in the experiments, both at the mean-field level and on utterly different networks, the observed level of cooperation is the same. We thus show that when human subjects interact in a heterogeneous mix including cooperators, defectors and moody conditional cooperators, the structure of the population does not promote or inhibit cooperation with respect to a well mixed population.

  13. Human Behavior Classification Using Multi-Class Relevance Vector Machine

    Directory of Open Access Journals (Sweden)

    Yogameena, B.

    2010-01-01

    Full Text Available Problem statement: In computer vision and robotics, one of the typical tasks is to identify specific objects in an image and to determine each object’s position and orientation relative to coordinate system. This study presented a Multi-class Relevance Vector machine (RVM classification algorithm which classifies different human poses from a single stationary camera for video surveillance applications. Approach: First the foreground blobs and their edges are obtained. Then the relevance vector machine classification scheme classified the normal and abnormal behavior. Results: The performance proposed by our method was compared with Support Vector Machine (SVM and multi-class support vector machine. Experimental results showed the effectiveness of the method. Conclusion: It is evident that RVM has good accuracy and lesser computational than SVM.

  14. Which activation function of cooperation describes human behavior?

    CERN Document Server

    Jarynowski, Andrzej

    2016-01-01

    Properties of cooperation's probability function in Prisoner`s Dilemma have impact on evolution of game. Basic model defines that probability of cooperation depends linearly, both on the player's altruism and the co-player's reputation. I propose modification of activation function to smooth one (hyperbolic tangent with scaling parameter a, which corresponds to its shape) and observe three phases for different range of a. (1) For small a, strategies seem to randomly change in time and situation of mixed choices (one cooperates and second defects) dominate. (2) For medium a, players choose only one strategy for given period of time (the common state can switch to opposite one with some probability). (3) For large a, mixed strategy (once defect, once cooperate) is coexisting with common strategies and no change is allowed. I believe that proposed function characterizes better socio-economical phenomena and especially phase 1 and 2 contain most of human behavior.

  15. Modeling human behavior in economics and social science.

    Science.gov (United States)

    Dolfin, M; Leonida, L; Outada, N

    2017-06-29

    The complex interactions between human behaviors and social economic sciences is critically analyzed in this paper in view of possible applications of mathematical modeling as an attainable interdisciplinary approach to understand and simulate the aforementioned dynamics. The quest is developed along three steps: Firstly an overall analysis of social and economic sciences indicates the main requirements that a contribution of mathematical modeling should bring to these sciences; subsequently the focus moves to an overview of mathematical tools and to the selection of those which appear, according to the authors bias, appropriate to the modeling; finally, a survey of applications is presented looking ahead to research perspectives. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Human turnover dynamics during sleep: Statistical behavior and its modeling

    Science.gov (United States)

    Yoneyama, Mitsuru; Okuma, Yasuyuki; Utsumi, Hiroya; Terashi, Hiroo; Mitoma, Hiroshi

    2014-03-01

    Turnover is a typical intermittent body movement while asleep. Exploring its behavior may provide insights into the mechanisms and management of sleep. However, little is understood about the dynamic nature of turnover in healthy humans and how it can be modified in disease. Here we present a detailed analysis of turnover signals that are collected by accelerometry from healthy elderly subjects and age-matched patients with neurodegenerative disorders such as Parkinson's disease. In healthy subjects, the time intervals between consecutive turnover events exhibit a well-separated bimodal distribution with one mode at ⩽10 s and the other at ⩾100 s, whereas such bimodality tends to disappear in neurodegenerative patients. The discovery of bimodality and fine temporal structures (⩽10 s) is a contribution that is not revealed by conventional sleep recordings with less time resolution (≈30 s). Moreover, we estimate the scaling exponent of the interval fluctuations, which also shows a clear difference between healthy subjects and patients. We incorporate these experimental results into a computational model of human decision making. A decision is to be made at each simulation step between two choices: to keep on sleeping or to make a turnover, the selection of which is determined dynamically by comparing a pair of random numbers assigned to each choice. This decision is weighted by a single parameter that reflects the depth of sleep. The resulting simulated behavior accurately replicates many aspects of observed turnover patterns, including the appearance or disappearance of bimodality and leads to several predictions, suggesting that the depth parameter may be useful as a quantitative measure for differentiating between normal and pathological sleep. These findings have significant clinical implications and may pave the way for the development of practical sleep assessment technologies.

  17. Human turnover dynamics during sleep: statistical behavior and its modeling.

    Science.gov (United States)

    Yoneyama, Mitsuru; Okuma, Yasuyuki; Utsumi, Hiroya; Terashi, Hiroo; Mitoma, Hiroshi

    2014-03-01

    Turnover is a typical intermittent body movement while asleep. Exploring its behavior may provide insights into the mechanisms and management of sleep. However, little is understood about the dynamic nature of turnover in healthy humans and how it can be modified in disease. Here we present a detailed analysis of turnover signals that are collected by accelerometry from healthy elderly subjects and age-matched patients with neurodegenerative disorders such as Parkinson's disease. In healthy subjects, the time intervals between consecutive turnover events exhibit a well-separated bimodal distribution with one mode at ⩽10 s and the other at ⩾100 s, whereas such bimodality tends to disappear in neurodegenerative patients. The discovery of bimodality and fine temporal structures (⩽10 s) is a contribution that is not revealed by conventional sleep recordings with less time resolution (≈30 s). Moreover, we estimate the scaling exponent of the interval fluctuations, which also shows a clear difference between healthy subjects and patients. We incorporate these experimental results into a computational model of human decision making. A decision is to be made at each simulation step between two choices: to keep on sleeping or to make a turnover, the selection of which is determined dynamically by comparing a pair of random numbers assigned to each choice. This decision is weighted by a single parameter that reflects the depth of sleep. The resulting simulated behavior accurately replicates many aspects of observed turnover patterns, including the appearance or disappearance of bimodality and leads to several predictions, suggesting that the depth parameter may be useful as a quantitative measure for differentiating between normal and pathological sleep. These findings have significant clinical implications and may pave the way for the development of practical sleep assessment technologies.

  18. Genomic imprinting and human psychology: cognition, behavior and pathology.

    Science.gov (United States)

    Goos, Lisa M; Ragsdale, Gillian

    2008-01-01

    Imprinted genes expressed in the brain are numerous and it has become clear that they play an important role in nervous system development and function. The significant influence of genomic imprinting during development sets the stage for structural and physiological variations affecting psychological function and behaviour, as well as other physiological systems mediating health and well-being. However, our understanding of the role of imprinted genes in behaviour lags far behind our understanding of their roles in perinatal growth and development. Knowledge of genomic imprinting remains limited among behavioral scientists and clinicians and research regarding the influence of imprinted genes on normal cognitive processes and the most common forms of neuropathology has been limited to date. In this chapter, we will explore how knowledge of genomic imprinting can be used to inform our study of normal human cognitive and behavioral processes as well as their disruption. Behavioural analyses of rare imprinted disorders, such as Prader-Willi and Angelman syndromes, provide insight regarding the phenotypic impact of imprinted genes in the brain, and can be used to guide the study of normal behaviour as well as more common but etiologically complex disorders such as ADHD and autism. Furthermore, hypotheses regarding the evolutionary development of imprinted genes can be used to derive predictions about their role in normal behavioural variation, such as that observed in food-related and social interactions.

  19. AUTHENTICITY OF HUMAN BEHAVIOR IN FREUD AND HEIDEGGER

    Directory of Open Access Journals (Sweden)

    IONUŢ ŞTEFAN

    2016-11-01

    Full Text Available The research theme is the question of the authenticity of human behavior examined from two perspectives: the psychoanalytical one, developed by Sigmund Freud, and the one of philosophy of being embodied by Martin Heidegger. As concerns the Freudian psychoanalysis, I am primarily interested in the conflict among: self, ego, and superego. Because of the requisitions of the supergo, the subject mostly behaves according to the censorships imposed by this psychic instance. The self, dominated by sexuality and aggressiveness, exhibits the pulsional tendency to manifest itself in the conscious behavior of the individual. As regards the Heideggerian endeavor, I am interested in distinguishing between the authentic and non-authentic existences. In Heidegger’s vision, the nonauthentic existence manifests when we are living together with the others in society. This is the horizon of the impersonal “as it is done”, the Heideggerian das Man, which may be understood by the three dimensions: curiosity, ambiguity, and chatter. The authentic existence manifests when the individuals live on their own, in privacy, and acknowledge the fact that their existence develops over a strictly determined time period, the imminent confrontation with their own death coming closer and closer.

  20. Social performance cues induce behavioral flexibility in humans

    NARCIS (Netherlands)

    Toelch, U.; Bruce, M.J.; Meeus, M.T.H.; Reader, S.M.

    2011-01-01

    Behavioral flexibility allows individuals to react to environmental changes, but changing established behavior carries costs, with unknown benefits. Individuals may thus modify their behavioral flexibility according to the prevailing circumstances. Social information provided by the performance leve

  1. Relative shrinkage of adipocytes by paraffin in proportion to plastic embedding in human adipose tissue before and after weight loss.

    Science.gov (United States)

    Verhoef, Sanne P M; van Dijk, Paul; Westerterp, Klaas R

    2013-01-01

    Adipocyte size is a major modulator of endocrine functioning of adipose tissue and methods allowing accurate determination of adipocyte size are important to study energy metabolism. The aim of this study was to assess the relative shrinkage of adipocytes before and after weight loss by comparing adipose tissue from the same subjects embedded in paraffin and plastic. 18 healthy subjects (5 males and 13 females) aged 20-50 y with a BMI of 28-38 kg/m² followed a very low energy diet for 8 weeks. Adipose tissue biopsies were taken prior to and after weight loss and were processed for paraffin and plastic sections. Parameters of adipocyte size were determined with computer image analysis. Mean adipocyte size was smaller in paraffin compared to plastic embedded tissue both before (66 ± 4 vs. 103 ± 5 μm, P paraffin embedded tissue in proportion to plastic embedded tissue was not significantly different before and after weight loss (73 and 69%, respectively). Shrinkage due to the type of embedding of the adipose tissue can be ignored when comparing before and after weight loss. Plastic embedding of adipose tissue provides more accurate and sensitive results. © 2013 Asian Oceanian Association for the Study of Obesity . Published by Elsevier Ltd. All rights reserved.

  2. Performance Analysis of a Fiber Reinforced Plastic Oil Cooler Cover Considering the Anisotropic Behavior of the Fiber Reinforced PA66

    Directory of Open Access Journals (Sweden)

    Jian Wang

    2016-09-01

    Full Text Available In this paper, a simulation method based on an orthogonal anisotropic material is proposed. A numerical example using a simple plate is presented to show the difference in the static performance between the orthogonal anisotropic and the isotropic models. Comparing with the tested modal data of a diesel engine oil cooler cover made by glass fiber reinforced polyamide 66 (PA66, the proposed simulation method was confirmed to be much closer to reality than the general isotropic model. After that, a comprehensive performance comparison between the plastic oil cooler covers with the orthogonal anisotropic and the isotropic fiber orientations was carried out including a static deformation and stress analysis under a pressure-temperature coupled load, a forced response analysis, and an acoustic analysis under real operating conditions. The results show that the stress, the deformation, the peak vibration velocity, and the overall sound power level of the orthogonal anisotropic model are different from that obtained with the isotropic model. More importantly, the proposed method can provide a much more detailed frequency content compared to the isotropic model.

  3. Microstructure and annealing behavior of a modified 9Cr-1Mo steel after dynamic plastic deformation to different strains

    Science.gov (United States)

    Zhang, Z. B.; Mishin, O. V.; Tao, N. R.; Pantleon, W.

    2015-03-01

    The microstructure, hardness and tensile properties of a modified 9Cr-1Mo steel processed by dynamic plastic deformation (DPD) to different strains (0.5 and 2.3) have been investigated in the as-deformed and annealed conditions. It is found that significant structural refinement and a high level of strength can be achieved by DPD to a strain of 2.3, and that the microstructure at this strain contains a large fraction of high angle boundaries. The ductility of the DPD processed steel is however low. Considerable structural coarsening of the deformed microstructure without pronounced recrystallization takes place during annealing of the low-strain and high-strain samples for 1 h at 650 °C and 600 °C, respectively. Both coarsening and partial recrystallization occur in the high-strain sample during annealing at 650 °C for 1 h. For this sample, it is found that whereas coarsening alone results in a loss of strength with only a small gain in ductility, coarsening combined with pronounced partial recrystallization enables a combination of appreciably increased ductility and comparatively high strength.

  4. Microstructure and annealing behavior of a modified 9Cr−1Mo steel after dynamic plastic deformation to different strains

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.B.; Mishin, O.V. [Danish-Chinese Center for Nanometals, Section for Materials Science and Advanced Characterization, Department of Wind Energy, Technical University of Denmark, Risø Campus, 4000 Roskilde (Denmark); Sino-Danish Center for Education and Research (China); Sino-Danish Center for Education and Research (Denmark); Tao, N.R. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China); Sino-Danish Center for Education and Research (China); Sino-Danish Center for Education and Research (Denmark); Pantleon, W., E-mail: pawo@dtu.dk [Section for Materials and Surface Engineering, Department of Mechanical Engineering, Technical University of Denmark, 2800 Kgs. Lyngby (Denmark); Sino-Danish Center for Education and Research (China); Sino-Danish Center for Education and Research (Denmark)

    2015-03-15

    The microstructure, hardness and tensile properties of a modified 9Cr−1Mo steel processed by dynamic plastic deformation (DPD) to different strains (0.5 and 2.3) have been investigated in the as-deformed and annealed conditions. It is found that significant structural refinement and a high level of strength can be achieved by DPD to a strain of 2.3, and that the microstructure at this strain contains a large fraction of high angle boundaries. The ductility of the DPD processed steel is however low. Considerable structural coarsening of the deformed microstructure without pronounced recrystallization takes place during annealing of the low-strain and high-strain samples for 1 h at 650 °C and 600 °C, respectively. Both coarsening and partial recrystallization occur in the high-strain sample during annealing at 650 °C for 1 h. For this sample, it is found that whereas coarsening alone results in a loss of strength with only a small gain in ductility, coarsening combined with pronounced partial recrystallization enables a combination of appreciably increased ductility and comparatively high strength.

  5. Integration of human behavior expectations in training: human behavior simulator; Integracion de las expectativas de comportamiento humano en la formacion: simulacion de comportamiento humano

    Energy Technology Data Exchange (ETDEWEB)

    Obeso Torices, E.

    2012-07-01

    The analysis of operating experience in nuclear Sta Maria de Garona point to fundamental human factor. After evaluation of the Peer Review, reinforcing behavior expectations was identified as improvement area. The human behavior simulator aims at minimizing human error. Making teamwork practices ensures that the equipment itself reinforces their behavior and performance in the work of the Central. The scope of practice to perform on the simulator includes all phases of execution. The team should analyze the best way to run, the impact of it on the ground and interaction with other sections, being the simulator training environment the situation closer to reality.

  6. From human behavior to the spread of mobile phone viruses

    Science.gov (United States)

    Wang, Pu

    Percolation theory was initiated some 50 years ago as a mathematical framework for the study of random physical processes such as the flow of a fluid through a disordered porous medium. It has been proved to be a remarkably rich theory, with applications from thermodynamic phase transitions to complex networks. In this dissertation percolation theory is used to study the diffusion process of mobile phone viruses. Some methodologies widely used in statistical physics are also applied to uncover the underlying statistical laws of human behavior and simulate the spread of mobile phone viruses in a large population. I find that while Bluetooth viruses can reach all susceptible handsets with time, they spread slowly due to human mobility, offering ample opportunities to deploy antiviral software. In contrast, viruses utilizing multimedia messaging services (MMS) could infect all users in hours, but currently a phase transition on the underlying call graph limits them to only a small fraction of the susceptible users. These results explain the lack of a major mobile virus breakout so far and predict that once a mobile operating system's market share reaches the phase transition point, viruses will pose a serious threat to mobile communications. These studies show how the large datasets and tools of statistical physics can be used to study some specific and important problems, such as the spread of mobile phone viruses.

  7. Group choice: the ideal free distribution of human social behavior.

    Science.gov (United States)

    Kraft, J R; Baum, W M

    2001-07-01

    Group choice refers to the distribution of group members between two choice alternatives over time. The ideal free distribution (IFD), an optimal foraging model from behavioral ecology, predicts that the ratio of foragers at two resource sites should equal the ratio of obtained resources, a prediction that is formally analogous to the matching law of individual choice, except that group choice is a social phenomenon. Two experiments investigated the usefulness of IFD analyses of human group choice and individual-based explanations that might account for the group-level events. Instead of nonhuman animals foraging at two sites for resources, a group of humans chose blue and red cards to receive points that could earn cash prizes. The groups chose blue and red cards in ratios in positive relation to the ratios of points associated with the cards. When group choice ratios and point ratios were plotted on logarithmic coordinates and fitted with regression lines, the slopes (i.e., sensitivity measures) approached 1.0 but tended to fall short of it (i.e., undermatching), with little bias and little unaccounted for variance. These experiments demonstrate that an IFD analysis of group choice is possible and useful, and suggest that group choice may be explained by the individual members' tendency to optimize reinforcement.

  8. Plasticity of Daily Behavioral Rhythms in Foragers and Nurses of the Ant Camponotus rufipes: Influence of Social Context and Feeding Times

    Science.gov (United States)

    Mildner, Stephanie; Roces, Flavio

    2017-01-01

    Daily activities within an ant colony need precise temporal organization, and an endogenous clock appears to be essential for such timing processes. A clock drives locomotor rhythms in isolated workers in a number of ant species, but its involvement in activities displayed in the social context is unknown. We compared locomotor rhythms in isolated individuals and behavioral rhythms in the social context of workers of the ant Camponotus rufipes. Both forager and nurse workers exhibited circadian rhythms in locomotor activity under constant conditions, indicating the involvement of an endogenous clock. Activity was mostly nocturnal and synchronized with the 12:12h light-dark-cycle. To evaluate whether rhythmicity was maintained in the social context and could be synchronized with non-photic zeitgebers such as feeding times, daily behavioral activities of single workers inside and outside the nest were quantified continuously over 24 hours in 1656 hours of video recordings. Food availability was limited to a short time window either at day or at night, thus mimicking natural conditions of temporally restricted food access. Most foragers showed circadian foraging behavior synchronized with food availability, either at day or nighttime. When isolated thereafter in single locomotor activity monitors, foragers mainly displayed arrhythmicity. Here, high mortality suggested potential stressful effects of the former restriction of food availability. In contrast, nurse workers showed high overall activity levels in the social context and performed their tasks all around the clock with no circadian pattern, likely to meet the needs of the brood. In isolation, the same individuals exhibited in turn strong rhythmic activity and nocturnality. Thus, endogenous activity rhythms were inhibited in the social context, and timing of daily behaviors was flexibly adapted to cope with task demands. As a similar socially-mediated plasticity in circadian rhythms was already shown in honey

  9. Predictive models of procedural human supervisory control behavior

    Science.gov (United States)

    Boussemart, Yves

    Human supervisory control systems are characterized by the computer-mediated nature of the interactions between one or more operators and a given task. Nuclear power plants, air traffic management and unmanned vehicles operations are examples of such systems. In this context, the role of the operators is typically highly proceduralized due to the time and mission-critical nature of the tasks. Therefore, the ability to continuously monitor operator behavior so as to detect and predict anomalous situations is a critical safeguard for proper system operation. In particular, such models can help support the decision J]l8king process of a supervisor of a team of operators by providing alerts when likely anomalous behaviors are detected By exploiting the operator behavioral patterns which are typically reinforced through standard operating procedures, this thesis proposes a methodology that uses statistical learning techniques in order to detect and predict anomalous operator conditions. More specifically, the proposed methodology relies on hidden Markov models (HMMs) and hidden semi-Markov models (HSMMs) to generate predictive models of unmanned vehicle systems operators. Through the exploration of the resulting HMMs in two distinct single operator scenarios, the methodology presented in this thesis is validated and shown to provide models capable of reliably predicting operator behavior. In addition, the use of HSMMs on the same data scenarios provides the temporal component of the predictions missing from the HMMs. The final step of this work is to examine how the proposed methodology scales to more complex scenarios involving teams of operators. Adopting a holistic team modeling approach, both HMMs and HSMMs are learned based on two team-based data sets. The results show that the HSMMs can provide valuable timing information in the single operator case, whereas HMMs tend to be more robust to increased team complexity. In addition, this thesis discusses the

  10. [Diversity and development of positional behavior in non-human primates].

    Science.gov (United States)

    Zhang, Jing; Qi, Xiao-Guang; Zhang, Kan; Zhang, Pei; Guo, Song-Tao; Wei, Wei; Li, Bao-Guo

    2012-10-01

    In long-term evolution, wildlife in general and primates in particular have formed specific patterns of behavior to adapt to a diverse variety of habitat environments. Current research on positional behavior in non-human primates has been found to explain a great deal about primate adaptability diversification, ecology, anatomy and evolution. Here, we summarize the noted classifications and differences in seasonal, site-specific and sex-age positional behaviors while also reviewing the development and status of non-human primate positional behavior research. This review is intended to provide reference for the future research of non-human primates and aid in further research on behavioral ecology of primates.

  11. Plastic bronchitis

    National Research Council Canada - National Science Library

    Singhi, Anil Kumar; Vinoth, Bharathi; Kuruvilla, Sarah; Sivakumar, Kothandam

    2015-01-01

    Plastic bronchitis, a rare but serious clinical condition, commonly seen after Fontan surgeries in children, may be a manifestation of suboptimal adaptation to the cavopulmonary circulation with unfavorable hemodynamics...

  12. Curcumin Alters Neural Plasticity and Viability of Intact Hippocampal Circuits and Attenuates Behavioral Despair and COX-2 Expression in Chronically Stressed Rats

    Science.gov (United States)

    Choi, Ga-Young; Kim, Hyun-Bum; Hwang, Eun-Sang; Lee, Seok; Kim, Min-Ji; Choi, Ji-Young; Lee, Sung-Ok

    2017-01-01

    Curcumin is a major diarylheptanoid component of Curcuma longa with traditional usage for anxiety and depression. It has been known for the anti-inflammatory, antistress, and neurotropic effects. Here we examined curcumin effect in neural plasticity and cell viability. 60-channel multielectrode array was applied on organotypic hippocampal slice cultures (OHSCs) to monitor the effect of 10 μM curcumin in long-term depression (LTD) through low-frequency stimulation (LFS) to the Schaffer collaterals and commissural pathways. Cell viability was assayed by propidium iodide uptake test in OHSCs. In addition, the influence of oral curcumin administration on rat behavior was assessed with the forced swim test (FST). Finally, protein expression levels of brain-derived neurotrophic factor (BDNF) and cyclooxygenase-2 (COX-2) were measured by Western blot in chronically stressed rats. Our results demonstrated that 10 μM curcumin attenuated LTD and reduced cell death. It also recovered the behavior immobility of FST, rescued the attenuated BDNF expression, and inhibited the enhancement of COX-2 expression in stressed animals. These findings indicate that curcumin can enhance postsynaptic electrical reactivity and cell viability in intact neural circuits with antidepressant-like effects, possibly through the upregulation of BDNF and reduction of inflammatory factors in the brain. PMID:28167853

  13. Study the Cyclic Plasticity Behavior of 508 LAS under Constant, Variable and Grid-Load-Following Loading Cycles for Fatigue Evaluation of PWR Components

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish [Argonne National Lab. (ANL), Argonne, IL (United States); Barua, Bipul [Argonne National Lab. (ANL), Argonne, IL (United States); Soppet, William K. [Argonne National Lab. (ANL), Argonne, IL (United States); Majumdar, Saurin [Argonne National Lab. (ANL), Argonne, IL (United States); Natesan, Ken [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    This report provides an update of an earlier assessment of environmentally assisted fatigue for components in light water reactors. This report is a deliverable in September 2016 under the work package for environmentally assisted fatigue under DOE’s Light Water Reactor Sustainability program. In an April 2016 report, we presented a detailed thermal-mechanical stress analysis model for simulating the stress-strain state of a reactor pressure vessel and its nozzles under grid-load-following conditions. In this report, we provide stress-controlled fatigue test data for 508 LAS base metal alloy under different loading amplitudes (constant, variable, and random grid-load-following) and environmental conditions (in air or pressurized water reactor coolant water at 300°C). Also presented is a cyclic plasticity-based analytical model that can simultaneously capture the amplitude and time dependency of the component behavior under fatigue loading. Results related to both amplitude-dependent and amplitude-independent parameters are presented. The validation results for the analytical/mechanistic model are discussed. This report provides guidance for estimating time-dependent, amplitude-independent parameters related to material behavior under different service conditions. The developed mechanistic models and the reported material parameters can be used to conduct more accurate fatigue and ratcheting evaluation of reactor components.

  14. Study on Rheology Behavior of Wood-Plastic Composites%木塑复合材料转矩流变性研究

    Institute of Scientific and Technical Information of China (English)

    徐冬梅; 张琳; 刘太闯; 袁晓龙; 曾长春

    2013-01-01

    Rheology behaviors of PVC,PP and PE-HD based wood-plastic composites were investigated by torque rheometer. The results show that wood powder content is the primary factor affecting rheology behavior. With the increase of wood powder content,the maximum torsional and equilibrium torque are improved,while fluidity is decreased. Processing fluidity of composite can be improved by adding coupling agent,compatibilizer and lubricant.%用转矩流变仪分别研究了聚氯乙烯、聚丙烯、高密度聚乙烯基木塑复合材料的转矩流变行为。结果表明,木粉用量是影响复合材料流变性的主要因素,随着木粉用量的增加,木塑复合材料的最大扭矩和平衡扭矩都提高,导致体系的流动性变差;采用偶联剂处理木粉和加入增容剂有助于改善体系的流动性;加入润滑剂也有利于熔体的流动。

  15. Plastic Fishes

    CERN Multimedia

    Trettnak, Wolfgang

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness. The slideshow below gives you a taste of the artworks by Wolfgang Trettnak and Margarita Cimadevila.

  16. Plastic Bridge

    Institute of Scientific and Technical Information of China (English)

    履之

    1994-01-01

    Already ubiquitous in homes and cars, plastic is now appearing inbridges. An academic-industrial consortium based at the University ofCalifornia in San Diego is launching a three-year research program aimed atdeveloping the world’s first plastic highway bridge, a 450-foot span madeentirely from glass-,carbon,and polymer-fiber-reinforced composite mate-rials, the stuff of military aircraft. It will cross Interstate 5 to connect thetwo sides of the school’s campus.

  17. Electrophysiological and Behavioral Evaluation of C-LTMR Plasticity Induced by Spinal Cord Injury: Transformation from Pleasure to Pain Afferents

    Science.gov (United States)

    2016-10-01

    include C-LTMRs, are indeed expanded after SCI . Receptive field of afferents representing A- LTMRs are also expanded after SCI . Figure 2D, shows that...and at varying time-points after SCI . We expect to show that (i) C-LTMRs receptive fields are indeed expanded after SCI and (ii) equate behavioral...allodynia-encoding nociceptors after SCI . Because C-LTMRs can be selectively identified by their expression of tyrosine hydroxylase (TH), all studies

  18. Aspects of elephant behavior, ecology, and interactions with humans

    Science.gov (United States)

    O'Connell, Caitlin Elizabeth

    This dissertation is comprised of two chapters relating to the acoustic behavior of elephants, their surrounding ecology and interactions with humans. The first chapter investigates the seismic aspects of Asian elephant (Elephus maximus) acoustic communication. The second chapter is comprised of a synthesis of two separate studies conducted on the African elephant (Loxodonta africana) in Namibia, both in Etosha National Park and the Caprivi region. The two studies were combined and published in Biological Conservation as one large study on aspects of the economic and social impacts of elephant/human conflict and experiments conducted to reduce conflict. In chapter one, seismic and acoustic data were recorded simultaneously from Asian elephants during periods of vocalizations and locomotion. Acoustic and seismic signals from rumbles were highly correlated at near and far distances and were in phase near the elephant and were out of phase at an increased distance from the elephant. Data analyses indicated that elephant generated signals associated with rumbles and "foot stomps" propagated at different velocities in the two media, the acoustic signals traveling at 309 m/s and the seismic signals at 248--264 m/s. Both types of signals had predominant frequencies in the range of 20 Hz. Seismic signal amplitudes considerably above background noise were recorded at 40 m from the generating elephants for both the rumble and the stomp. Seismic propagation models suggest that seismic waveforms from vocalizations are potentially detectable by instruments at distances of up to 16 km, and up to 32 km for locomotion generated signals. Thus, if detectable by elephants, these seismic signals could be useful for long distance communication. In chapter two, the economic impact of elephants, Loxodonta africana , and predators, particularly lions, Panthera leo, on rural agriculturists in the Kwando region of the East Caprivi, Namibia was assessed from the years 1991 to 1995. Elephants

  19. Human toddlers' attempts to match two simple behaviors provide no evidence for an inherited, dedicated imitation mechanism.

    Directory of Open Access Journals (Sweden)

    Susan S Jones

    Full Text Available Influential theories of imitation have proposed that humans inherit a neural mechanism - an "active intermodal matching " (AIM mechanism or a mirror neuron system - that functions from birth to automatically match sensory input from others' actions to motor programs for performing those same actions, and thus produces imitation. To test these proposals, 160 1- to 2½-year-old toddlers were asked to imitate two simple movements- bending the arm to make an elbow, and moving the bent elbow laterally. Both behaviors were almost certain to be in each child's repertoire, and the lateral movement was goal-directed (used to hit a plastic cup. Thus, one or both behaviors should have been imitable by toddlers with a functioning AIM or mirror neuron system. Each child saw the two behaviors repeated 18 times, and was encouraged to imitate. Children were also asked to locate their own elbows. Almost no children below age 2 imitated either behavior. Instead, younger children gave clear evidence of a developmental progression, from reproducing only the outcome of the models' movements (hitting the object, through trying (but failing to reproduce the model's arm posture and/or the arm-cup relations they had seen, to accurate imitation of arm bending by age 2 and of both movements by age 2½. Across age levels, almost all children who knew the word 'elbow' imitated both behaviors: very few who did not know the word imitated either behavior. The evidence is most consistent with a view of early imitation as the product of a complex system of language, cognitive, social, and motor competencies that develop in infancy. The findings do not rule out a role for an inherited neural mechanism, but they suggest that such a system would not by itself be sufficient to explain imitation at any age.

  20. Simulating irrational human behavior to prevent resource depletion.

    Directory of Open Access Journals (Sweden)

    Anna Sircova

    Full Text Available In a situation with a limited common resource, cooperation between individuals sharing the resource is essential. However, people often act upon self-interest in irrational ways that threaten the long-term survival of the whole group. A lack of sustainable or environmentally responsible behavior is often observed. In this study, we examine how the maximization of benefits principle works in a wider social interactive context of personality preferences in order to gain a more realistic insight into the evolution of cooperation. We used time perspective (TP, a concept reflecting individual differences in orientation towards past, present, or future, and relevant for making sustainable choices. We developed a personality-driven agent-based model that explores the role of personality in the outcomes of social dilemmas and includes multiple facets of diversity: (1 The agents have different behavior strategies: individual differences derived by applying cluster analysis to survey data from 22 countries (N = 10,940 and resulting in 7 cross-cultural profiles of TP; (2 The non-uniform distribution of the types of agents across countries; (3 The diverse interactions between the agents; and (4 diverse responses to those interactions in a well-mixed population. As one of the results, we introduced an index of overall cooperation for each of the 22 countries, which was validated against cultural, economic, and sustainability indicators (HDI, dimensions of national culture, and Environment Performance Index. It was associated with higher human development, higher individualism, lower power distance, and better environmental performance. The findings illustrate how individual differences in TP can be simulated to predict the ways people in different countries solve the personal vs. common gain dilemma in the global limited-resource situation. This interdisciplinary approach to social simulation can be adopted to explain the possible causes of global

  1. GREEN PLASTIC: A NEW PLASTIC FOR PACKAGING

    OpenAIRE

    Mr. Pankaj Kumar*, Sonia

    2016-01-01

    This paper gives a brief idea about a new type of plastic called as bio-plastic or green plastic. Plastic is used as a packaging material for various products, but this plastic is made up of non renewable raw materials. There are various disadvantages of using conventional plastic like littering, CO2 production, non-degradable in nature etc. To overcome these problems a new type of plastic is discovered called bio-plastic or green plastic. Bio-plastic is made from renewable resources and also...

  2. MUTZ-3 derived Langerhans cells in human skin equivalents show differential migration and phenotypic plasticity after allergen or irritant exposure

    NARCIS (Netherlands)

    Kosten, I.J.; Spiekstra, S.W.; de Gruijl, T.D.; Gibbs, S.

    2015-01-01

    After allergen or irritant exposure, Langerhans cells (LC) undergo phenotypic changes and exit the epidermis. In this study we describe the unique ability of MUTZ-3 derived Langerhans cells (MUTZ-LC) to display similar phenotypic plasticity as their primary counterparts when incorporated into a phys

  3. Developmental Plasticity in Child Growth and Maturation

    Directory of Open Access Journals (Sweden)

    Ze'ev eHochberg

    2011-09-01

    Full Text Available The ability of a given genotype to produce different phenotypes in response to different environments is termed "plasticity", and is part of the organism's "adaptability" to environmental cues. The expressions of suites of genes, particularly during development or life-history transitions, probably underlie the fundamental plasticity of an organism. Plasticity in developmental programming has evolved in order to provide the best chances of survival and reproductive success to organisms under changing environments. Environmental conditions that are experienced in early life can profoundly influence human biology, child growth and maturation, and long-term health and longevity. Developmental origins of health and disease and life history transitions are purported to use placental, nutritional, and endocrine cues for setting long-term biological, mental, and behavioral strategies for child growth and maturation in response to local ecological and/or social conditions. The window of developmental plasticity extends from conception to early childhood, and even beyond to the transition from juvenility to adoelscence, and could be transmitted transgenerationally. It involves epigenetic responses to environmental changes, which exert their effects during life history phase-transitions.

  4. Developmental plasticity in child growth and maturation.

    Science.gov (United States)

    Hochberg, Ze'ev

    2011-01-01

    The ability of a given genotype to produce different phenotypes in response to different environments is termed "plasticity," and is part of the organism's "adaptability" to environmental cues. The expressions of suites of genes, particularly during development or life history transitions, probably underlie the fundamental plasticity of an organism. Plasticity in developmental programming has evolved in order to provide the best chances of survival and reproductive success to organisms under changing environments. Environmental conditions that are experienced in early life can profoundly influence human biology, child growth and maturation, and long-term health and longevity. Developmental origins of health and disease and life history transitions are purported to use placental, nutritional, and endocrine cues for setting long-term biological, mental, and behavioral strategies for child growth and maturation in response to local ecological and/or social conditions. The window of developmental plasticity extends from conception to early childhood, and even beyond to the transition from juvenility to adolescence, and could be transmitted transgenerationally. It involves epigenetic responses to environmental changes, which exert their effects during life history phase transitions.

  5. Integrative approaches utilizing oxytocin to enhance prosocial behavior: from animal and human social behavior to autistic social dysfunction.

    Science.gov (United States)

    Yamasue, Hidenori; Yee, Jason R; Hurlemann, René; Rilling, James K; Chen, Frances S; Meyer-Lindenberg, Andreas; Tost, Heike

    2012-10-10

    The prevalence of autism spectrum disorder (ASD) is as high as 1 in 100 individuals and is a heavy burden to society. Thus, identifying causes and treatments is imperative. Here, we briefly review the topics covered in our 2012 Society for Neuroscience Mini-Symposium entitled "Integrative Approaches Using Oxytocin to Enhance Prosocial Behavior: From Animal and Human Social Behavior to ASD's Social Dysfunction." This work is not meant to be a comprehensive review of oxytocin and prosocial behavior. Instead, we wish to share the newest findings on the effects of oxytocin on social behavior, the brain, and the social dysfunction of ASD at the molecular, genetic, systemic, and behavior levels, in varied subjects ranging from animal models to humans suffering from autism for the purpose of promoting further study for developing the clinical use of oxytocin in treating ASD.

  6. Differential modulation of motor cortical plasticity and excitability in early and late phases of human motor learning.

    Science.gov (United States)

    Rosenkranz, Karin; Kacar, Aleksandra; Rothwell, John C

    2007-10-31

    Different phases of motor skill learning appear to involve different physiological processes, with long-term potentiation (LTP) occurring at existing synapses in early and cortical reorganization involving synaptogenesis in later phases. Here, we test the evolution of skill learning-dependent changes in motor plasticity and excitability in six subjects trained to perform rapid thumb abductions over 5 d. Plasticity was examined using paired-associative stimulation (PAS) of the median nerve and motor cortex to induce LTP-like "PAS given with an interstimulus interval of 25 ms (PAS25)" or long-term depression (LTD)-like "PAS given with an interstimulus interval of 10 ms (PAS10)" plasticity. Excitability was tested by measuring recruitment of motor-evoked-potentials "input-output (IO) curve" and of short-latency intracortical inhibition (SICI curve), and sensorimotor organization (SMO). Task performance improved continuously over 5 d. After practice on day 1, the PAS25 effect reversed from facilitation to inhibition whereas the slope of the IO curve increased and the level of SICI decreased. These effects on IO curve and SICI were still present or even enhanced before the last practice on day 5, and were not changed by it. The effect of proprioceptive input from the trained muscle on SMO was also strengthened before practice on day 5. In contrast, PAS-induced plasticity was not influenced by motor practice on day 5, and had returned to prepractice values. The interference with PAS-induced plasticity suggests that the initial performance improvement relies on increasing the efficacy of existing synaptic connections. However, the long-lasting changes in the IO curve, SICI curve, and SMO suggest that continued practice enhances performance by changing Motor cortical organization. We hypothesize that new synaptic connections might have formed that allow LTP/LTD-susceptibility to be restored without reducing synaptic strength and performance skill.

  7. [Cortical plasticity in blind individual].

    Science.gov (United States)

    Wang, Shu-zhen; Zhu, Si-quan

    2008-10-01

    The cognitive mechanisms and functional brain imaging research on blind individuals provide special information for exploring the plasticity of the developing human brain. This paper focuses on five aspects of recent progress in this field: (1) the behavior compensation of the blind; (2) the influence of early visual deprivation and later visual deprivation on cross-modal reorganization; (3) the relationship between the complexity of task requirement and cross-modal reorganization; (4) the relationship between the sensitive periods of the visual system and the time course of cross-modal reorganization; (5) the neural mechanisms of cross-modal reorganization. These findings contribute greatly to the theoretical basis of the rehabilitation of individuals with perceptual deficits.

  8. Relationships Analysis and Public Perception of the Healthy Plastic as One Solution to Healthy Living

    Science.gov (United States)

    Hartatik; Hartono, R.; Purnomo, A.; Riasti, B. K.; Munawaroh, H.

    2017-02-01

    Direct Plastics are used for various human purposes, ranging from household to industry. Tableware and drink made of plastic is very practical to use, easy to clean, durable and cost far less than tableware made of the other material. However, must also be considered in terms of security in the use of plastic containers for food storage because there are adverse effects. There are seven types of plastic based material used, namely Polyethylene, Terephthalate, High Density Polyethylene, Polyvinyl Chloride or V/PVC, Low Density Polyethylene or LDPE, Polypropylene, Polystyrene, Plastics others including polycarbonate. Experts claims that the plastic code numbers 2, 4 and 5 are used for equipment safely eat/drink because it is more stable and safe if used correctly. In this study will analyze the relationship between the recent education, family income to perception and behavior in the use of plastics in food storage daily as one solution to healthy living. The population of this research is all the people in the Solo area particularly housewife and all the people in the productive age. Data were obtained through a survey with cluster random sampling method. Statistical method used is a parametric method and Chi Square test This method is used as an alternative method of parametric when some assumptions are not met. Based on the results of Chi Square test with α = 15% was concluded that recent education and income related to the behavior of people using plastic products as one of the solutions to Healthy Living.

  9. Supporting Negotiation Behavior with Haptics-Enabled Human-Computer Interfaces

    OpenAIRE

    Küçükyılmaz, Ayşe; Sezgin, Tevfik Metin; Başdoğan, Çağatay

    2012-01-01

    An active research goal for human-computer interaction is to allow humans to communicate with computers in an intuitive and natural fashion, especially in real-life interaction scenarios. One approach that has been advocated to achieve this has been to build computer systems with human-like qualities and capabilities. In this paper, we present insight on how human-computer interaction can be enriched by employing the computers with behavioral patterns that naturally appear in human-human nego...

  10. The momentum of human behavior in a natural setting

    OpenAIRE

    Mace, F. Charles; Lalli, Joseph S.; Shea, Michael C.; Lalli, Elizabeth Pinter; West, Barbara J.; Roberts, Maura; Nevin, John A.

    1990-01-01

    Adults with mental retardation in a group home received popcorn or coffee reinforcers for sorting plastic dinnerware. In Part 1 of the experiment, reinforcers were dispensed according to a variable-interval 60-s schedule for sorting dinnerware of one color and according to a variable-interval 240-s schedule for sorting dinnerware of a different color in successive components of a multiple schedule. Sorting rates were similar in baseline, but when a video program was shown concurrently, sortin...

  11. Effect of elastic-plastic behavior of coating layer on drawability and frictional characteristic of galvannealed steel sheets

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seong Won; Lee, Jung Min [Korea Institute of Industrial Technology, Jinju (Korea, Republic of); Joun, Man Soo [Gyeongsang National University, Jinju (Korea, Republic of); Kim, Dong Hwan [International University of Korea, Jinju (Korea, Republic of)

    2016-07-15

    During a galvannealed sheet metal forming, the failures of coating layers (powdering, flaking and cracking) frequently affect the strain state of sheets and deteriorate the frictional characteristic between sheets and tools. Two FE-models in this study were suggested to investigate the effects of the mechanical behavior of coating layers on the formability and friction of the coated steel sheets in FE analysis; the first is one-layer model to express the coated sheet as one stress-strain curve and the second is a multiple-layer model which is composed of substrates and coating layers, separately. First, the frictional properties and the formability of the coated sheets were experimentally investigated using a cup deep-drawing trial. After, the drawing process was simulated by FE analysis of the two models. In the multiplelayer model, the mechanical behavior of the coating is defined as a stress-strain curve which was determined using the nanoindentation test of the coating, its FE analysis and artificial neural network method. The result showed that the multiple-layer model provides more accuracy predictions of drawing loads than the one-layer model in the FE analysis, compared to the actual cup drawing test.

  12. "Anatomical simulation" of the biomechanical behavior of the human mandible.

    Science.gov (United States)

    Kober, Cornelia; Hellmich, Christian; Stübinger, Stefan; Zeilhofer, Hans-Florian; Sader, Robert

    2015-01-01

    The load-carrying behavior of the human mandible can be described using finite element simulation, enabling investigations about physiological and pathological skeletal adaption. "Anatomical simulation" implies a stepwise approximation towards the anatomical reality. The project is structured in three steps. In Step 1, the preprocessing, the simulation model is provided. Step 2 is the numerical computation. Step 3 is dedicated to the interpretation of the results. The requirements of the preprocessing are: a) realization of the organ's individual anatomy, namely its outer shape; b) the tissue's elastic properties, thus its inner consistency; and c) the organ's mechanical loads. For physiological mandibular loading, these are due to muscles, temporomandibular joints, and tooth forces. Meanwhile, the reconstruction of the macroscopic anatomy from computed tomography data is standard. The periodontal ligament is inserted ex post using an approach developed by the authors. The bone is modeled anisotropically and inhomogeneously. By the visualization of the individual fiber course, the muscular force vectors are realized. The mandibular condyle is freely mobile in a kind of simplified joint capsule. For the realization of bite forces, several approaches are available. An extendible software tool is provided, enabling the user - by variable input of muscle and bite forces - to examine the individual patient's biomechanics, eg, the influence of the periodontal ligament, the condition of the temporomandibular joints, atrophic processes, or the biomechanical situation of dental implants. By stepwise approximation towards the anatomical reality, the mandibular simulation will be advanced to a valuable tool for diagnosis and prognosis.

  13. Linear and nonlinear behavior of human and artificial lip reeds

    Science.gov (United States)

    Campbell, Murray; Richards, Orlando

    2003-10-01

    In a musical instrument of the lip reed aerophone class, the flow of air from the player's lungs into the resonating air column is modulated by the periodic opening and closing of the pressure-controlled valve formed by the player's lips. The nature of the operation of this valve has been the subject of considerable study in recent years. Since the pressure-flow relationship is strongly nonlinear, the behavior of the coupled system of lips and air column can only be modeled using the methods of nonlinear dynamics. Extensive studies of artificial lip reeds, in which the lips are simulated by water-filled latex tubes, have shown them to be capable of reproducing musically important features of human playing, including the lipping of notes both below and above an acoustic resonance of the air column. Measurements of the linear response of artificial reeds have guided the development of more realistic models of the lip reed, while studies of both real and artificial lips using a high-speed digital camera have shed fresh light on the nature of the lip motion at the large amplitudes typical of loud playing. [Work supported by EPSRC.

  14. Modeling Humans as Reinforcement Learners: How to Predict Human Behavior in Multi-Stage Games

    Science.gov (United States)

    Lee, Ritchie; Wolpert, David H.; Backhaus, Scott; Bent, Russell; Bono, James; Tracey, Brendan

    2011-01-01

    This paper introduces a novel framework for modeling interacting humans in a multi-stage game environment by combining concepts from game theory and reinforcement learning. The proposed model has the following desirable characteristics: (1) Bounded rational players, (2) strategic (i.e., players account for one anothers reward functions), and (3) is computationally feasible even on moderately large real-world systems. To do this we extend level-K reasoning to policy space to, for the first time, be able to handle multiple time steps. This allows us to decompose the problem into a series of smaller ones where we can apply standard reinforcement learning algorithms. We investigate these ideas in a cyber-battle scenario over a smart power grid and discuss the relationship between the behavior predicted by our model and what one might expect of real human defenders and attackers.

  15. Ontology-based Deep Learning for Human Behavior Prediction with Explanations in Health Social Networks.

    Science.gov (United States)

    Phan, Nhathai; Dou, Dejing; Wang, Hao; Kil, David; Piniewski, Brigitte

    2017-04-01

    Human behavior modeling is a key component in application domains such as healthcare and social behavior research. In addition to accurate prediction, having the capacity to understand the roles of human behavior determinants and to provide explanations for the predicted behaviors is also important. Having this capacity increases trust in the systems and the likelihood that the systems actually will be adopted, thus driving engagement and loyalty. However, most prediction models do not provide explanations for the behaviors they predict. In this paper, we study the research problem, human behavior prediction with explanations, for healthcare intervention systems in health social networks. We propose an ontology-based deep learning model (ORBM(+)) for human behavior prediction over undirected and nodes-attributed graphs. We first propose a bottom-up algorithm to learn the user representation from health ontologies. Then the user representation is utilized to incorporate self-motivation, social influences, and environmental events together in a human behavior prediction model, which extends a well-known deep learning method, the Restricted Boltzmann Machine. ORBM(+) not only predicts human behaviors accurately, but also, it generates explanations for each predicted behavior. Experiments conducted on both real and synthetic health social networks have shown the tremendous effectiveness of our approach compared with conventional methods.

  16. Human Behavior, Social Environment, Social Reconstruction, and Social Policy: A System of Linkages, Goals, and Priorities.

    Science.gov (United States)

    Mohan, Brij

    1980-01-01

    The idea of a wholesome relationship between human behavior and the forces of social environment is explored. The goals and foci of the human behavior and social environment component in social work education are reconceptualized in the light of knowledge that underscores the need for social reconstruction. (Author/MLW)

  17. Choice, Communication, and Conflict. A System's Approach to the Study of Human Behavior.

    Science.gov (United States)

    Ackoff, Russell L.

    This book presents a teleological analysis of the concepts of human behavior. Through distinctions and definitions, a model or system is developed, upon which all aspects of behavior are interrelated. The model of choice or purposeful state is discussed with its underlying concepts. Human communication and feeling, and cooperation and conflict…

  18. Ontology-based high-level context inference for human behavior identification

    NARCIS (Netherlands)

    Villalonga, Claudia; Razzaq, Muhammad Asif; Ali Khan, Wajahat; Pomares, Hector; Rojas, Ignacio; Lee, Sungyoung; Banos Legran, Oresti

    2016-01-01

    Recent years have witnessed a huge progress in the utomatic identification of individual primitives of human behavior, such as activities or locations. However, the complex nature of human behavior demands more abstract contextual information for its analysis. This work presents an ontology-based

  19. Plastic condoms.

    Science.gov (United States)

    1968-01-01

    Only simple equipment, simple technology and low initial capital investment are needed in their manufacture. The condoms can be made by people who were previously unskilled or only semi-skilled workers. Plastic condoms differ from those made of latex rubber in that the nature of the plastic film allows unlimited shelf-life. Also, the plastic has a higher degree of lubricity than latex rubber; if there is a demand for extra lubrication in a particular market, this can be provided. Because the plastic is inert, these condoms need not be packaged in hermetically sealed containers. All these attributes make it possible to put these condoms on the distributors' shelves in developing countries competitively with rubber condoms. The shape of the plastic condom is based on that of the lamb caecum, which has long been used as luxury-type condom. The plastic condom is made from plastic film (ethylene ethyl acrilate) of 0.001 inch (0.0254 mm.) thickness. In addition, a rubber ring is provided and sealed into the base of the condom for retention during coitus. The advantage of the plastic condom design and the equipment on which it is made is that production can be carried out either in labour-intensive economy or with varying degrees of mechanization and automation. The uniform, finished condom if made using previously untrained workers. Training of workers can be done in a matter of hours on the two machines which are needed to produce and test the condoms. The plastic film is provided on a double wound roll, and condom blanks are prepared by means of a heat-sealing die on the stamping machine. The rubber rings are united to the condom blanks on an assembly machine, which consists of a mandrel and heat-sealing equipment to seal the rubber ring to the base of the condom. Built into the assembly machine is a simple air-testing apparatus that can detect the smallest pinhole flaw in a condom. The manufacturing process is completed by unravelling the condom from the assembly

  20. Plastic Bronchitis.

    Science.gov (United States)

    Rubin, Bruce K

    2016-09-01

    Plastic bronchitis is an uncommon and probably underrecognized disorder, diagnosed by the expectoration or bronchoscopic removal of firm, cohesive, branching casts. It should not be confused with purulent mucous plugging of the airway as seen in patients with cystic fibrosis or bronchiectasis. Few medications have been shown to be effective and some are now recognized as potentially harmful. Current research directions in plastic bronchitis research include understanding the genetics of lymphatic development and maldevelopment, determining how abnormal lymphatic malformations contribute to cast formation, and developing new treatments. Copyright © 2016 Elsevier Inc. All rights reserved.